Filed Pursuant to Rule 424(b)(5)
Registration No. 333-234325

Prospectus supplement
(To prospectus dated October 25, 2019)

 

Investing in the notes involves significant risks. See “Risk Factors” beginning on page S-9 of this prospectus supplement and on page 1 of the accompanying prospectus.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We expect that the notes will be ready for delivery in book-entry-only form through The Depository Trust Company on August 14, 2020.

Co-Managers

August 11, 2020

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus and any free writing prospectus we authorize for use in connection with this offering. We have not, and the underwriters have not, authorized anyone to provide you with information that is different. This prospectus supplement and the accompanying prospectus are not an offer to sell or a solicitation of an offer to buy these securities in any circumstances under which the offer or sale is unlawful. We are offering to sell, and seeking offers to buy, notes only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the notes in certain jurisdictions may be restricted by law. You should assume that the information included, or incorporated by reference, in this prospectus supplement or the accompanying prospectus is accurate only as of the date of this prospectus supplement, the accompanying prospectus or the information we have incorporated by reference. Our financial condition, results of operations and business prospects may have changed since those dates.

This prospectus supplement, the accompanying prospectus, any free writing prospectus we authorize for use in connection with this offering and the information incorporated by reference herein and therein contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Forward-looking statements give our current expectations or forecasts of future events. All statements included herein or incorporated by reference herein that are predictive in nature, that depend upon or refer to future events or conditions, or that use terms and phrases such as “achieve,” “anticipate,” “believe,” “estimate,” “budget,” “expect,” “forecast,” “plan,” “project,” “propose,” “strategy,” “predict,” “envision,” “hope,” “intend,” “will,” “continue,” “may,” “potential,” “should,” “could” and similar terms and phrases are forward-looking statements, although not all forward-looking statements contain such identifying words. Included in forward-looking statements are, among other things:

Although we believe that the expectations reflected in our forward-looking statements are reasonable and are based on reasonable assumptions, they do involve risks, uncertainties and other factors that could cause actual results to differ materially from those in the forward-looking statements. These factors include:

Our actual results could also differ materially from those anticipated in any forward-looking statements as a result of a variety of factors, including those discussed in “Risk Factors” and in other sections of this prospectus supplement and those discussed under “Risk Factors” in the accompanying prospectus and elsewhere in the documents that we incorporate by reference herein, including in “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” under the heading “Economic Outlook and

Industry Influences” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2019, our subsequent Quarterly Reports on Form 10-Q and in our other reports filed with the U.S. Securities and Exchange Commission (“SEC”). All forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by these risk factors. We caution you not to place undue reliance on the forward-looking statements. Forward-looking statements are only as of the date they are made, and other than as required under the securities laws, we assume no obligation to update or revise these forward-looking statements or provide reasons why actual results may differ.

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filed with the SEC. Certain information in the registration statement has been omitted from this prospectus supplement and the accompanying prospectus in accordance with the rules of the SEC. We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the internet at the SEC’s website at www.sec.gov. You can also obtain information about us at the offices of the New York Stock Exchange, 20 Broad Street, New York, New York 10005. You may find additional information about us on our website at www.helixesg.com, where we post our SEC filings. The information contained on, or that can be accessed through, our website (other than the specified SEC filings incorporated by reference in this prospectus supplement and the accompanying prospectus) is not a part of this prospectus supplement or the accompanying prospectus and is not incorporated by reference herein or therein. You should not consider such information contained on our website or that can be accessed through our website to be part of this prospectus supplement or the accompanying prospectus.

We incorporate by reference information into this prospectus supplement and the accompanying prospectus, which means that we disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus supplement and the accompanying prospectus, and information that we file later with the SEC will automatically update and supersede this information. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement and the accompanying prospectus. Unless this prospectus supplement, the accompanying prospectus or the information incorporated by reference herein and therein indicates that another date applies, you should not assume that the information in this prospectus supplement and the accompanying prospectus is current as of any date other than the date of this prospectus supplement and the accompanying prospectus or that any information we have incorporated by reference herein or therein is accurate as of any date other than the date of the document incorporated by reference.

We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (excluding information furnished and not filed in accordance with SEC rules) on or after the date of this prospectus supplement until we have sold all of the notes to which this prospectus supplement relates or the offering is otherwise terminated. These reports contain important information about us, our financial condition and our results of operations:

You may request a copy of our filings, at no cost, by writing or telephoning us at the following address or phone number:

Corporate Secretary
Helix Energy Solutions Group, Inc.
3505 West Sam Houston Parkway North, Suite 400
Houston, Texas 77043
(281) 618-0400

Investing in the notes involves risks. Prior to making a decision whether to invest in the notes, and in consultation with your own financial and legal advisors, you should carefully consider, among other matters, the following risk factors as well as those incorporated by reference in this prospectus supplement from our Annual Report on Form 10-K for the year ended December 31, 2019 and in our subsequent Quarterly Reports on Form 10-Q under the headings “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and in our other filings we may make from time to time.

The notes are unsecured, are effectively subordinated to all of our existing and future secured indebtedness, to the extent of the assets securing such indebtedness and other secured obligations (to the extent of the value of the assets securing such indebtedness and other obligations, and are structurally subordinated to all liabilities of our subsidiaries, including trade payables. Our obligations under our credit agreement are guaranteed by our domestic subsidiaries (except Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited (formerly known as Canyon Offshore Limited) and Helix Well Ops (UK) Limited, each wholly owned Scottish subsidiaries, and are secured by pledges or mortgages of (i) most of our assets, (ii) the shares of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited, and (iii) most of the assets of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited. In addition, these obligations are secured by pledges of up to 66% of the shares of certain foreign subsidiaries. See “Description of Other Indebtedness—Credit Agreement.” As of June 30, 2020, we had approximately $386.86 million of consolidated indebtedness outstanding, net of unamortized discounts and issuance costs, of which approximately $258.95 million was indebtedness of Helix Energy Solutions Group, Inc., including approximately $31.21 million of secured indebtedness, and approximately $127.91 million of which was indebtedness of our subsidiaries.

In the event of our insolvency, bankruptcy, liquidation, reorganization, dissolution or winding up, we may not have sufficient assets to pay amounts due on any or all of the notes then outstanding. See “Description of Notes—Ranking.”

None of our subsidiaries has guaranteed or otherwise become obligated with respect to the notes. Our right to receive assets from any of our subsidiaries upon its liquidation or reorganization, and the right of holders of the notes to participate in those assets, is structurally subordinated to claims of that subsidiary’s creditors, including trade creditors. Even if we were a creditor of any of our subsidiaries, our rights as a creditor would be subordinate to any security interest in the assets of that subsidiary and any indebtedness of that subsidiary senior to that held by us. Furthermore, none of our subsidiaries is under any obligation to make payments to us, and any payments to us would depend on the earnings or financial condition of our subsidiaries and various business considerations. Statutory, contractual or other restrictions may also limit our subsidiaries’ ability to pay dividends or make distributions, loans or advances to us. For these reasons, we may not have access to any assets or cash flows of our subsidiaries to make payments on the notes.

Any issuance of equity securities after this offering, including any issuance of shares of our common stock upon conversion of the notes, or our Existing Notes, or to our employees and directors under our long term incentive plans, will dilute the interests of our existing shareholders, including holders who have received shares of our common stock upon conversion of their notes, and could substantially decrease the trading price of our common stock and the notes. We may issue equity securities in the future for a number of reasons, including to finance our operations and business strategy (including in connection with acquisitions, strategic collaborations or other transactions), to adjust our ratio of debt to equity, to satisfy our obligations upon the exercise of outstanding warrants or options or for other reasons.

In addition, the price of our common stock could also be affected by possible sales of our common stock by investors who view the notes as a more attractive means of equity participation in our company and by hedging

or arbitrage trading activity that we expect to develop involving our common stock. The hedging or arbitrage could, in turn, affect the trading price of the notes or any common stock that holders receive upon conversion of the notes.

The trading price of our common stock has been, and is likely to continue to be, volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control. Global stock markets in general, and stock prices of public oil and gas companies in particular, have recently experienced extreme volatility primarily as a result of the ongoing COVID-19 pandemic and the OPEC+ price war during the first quarter 2020. In addition to the factors discussed in these risk factors and elsewhere in our reports and other documents filed with the SEC, factors that may cause volatility in our share price include:

Furthermore, from time to time, the stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as general economic, political and market conditions, such as recessions, interest rate changes, international currency fluctuations or political unrest, may negatively impact the market price of our common stock. In the past, companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation, and we have been a defendant to a securities class action claim in the past. Any future securities litigation against us could result in substantial costs and divert our management’s attention.

As described under “Description of Notes—Adjustments to the Conversion Rate,” we will adjust the conversion rate of the notes for certain events, including, among others:

We will not adjust the conversion rate for other events, such as an issuance of our common stock for cash or in connection with an acquisition, that may adversely affect the trading price of the notes or our common stock. If we engage in any of these types of transactions, the value of the shares of common stock underlying your notes may be diluted. An event that adversely affects the value of the notes, but does not result in an adjustment to the conversion rate, may occur. Also, we will not increase the conversion rate to an amount that exceeds 207.9002 shares of common stock per $1,000 principal amount of notes (subject to adjustment in the same manner as the conversion rate).

Our election to deliver cash in respect of all or a portion of our conversion obligation (other than solely cash in lieu of fractional shares) as described under “Description of Notes—Conversion Rights,” may:

We will generally deliver the consideration due upon conversion of the notes as soon as practicable, but in no event later than two business days after (1) the last trading day in the observation period (in the case of cash settlement or combination settlement) or (2) the conversion date (in the case of physical settlement). In addition, in the case of cash settlement or combination settlement, because the consideration due upon conversion is based on the trading prices of our common stock during the observation period, any decrease in the price of our common stock after you surrender your notes for conversion may significantly decrease the value of the consideration you receive upon conversion. In addition, if the trading price of our common stock at the end of such period is below the average of the volume-weighted average price of our common stock during such period, the value of any shares of common stock that you receive in satisfaction of our conversion obligation will be less than the value used to determine the number of shares of common stock you will receive.

The accounting method for reflecting the notes on our balance sheet, accruing interest expense for the notes and reflecting the underlying shares of our common stock in our reported diluted earnings per share may adversely affect our reported earnings and financial condition.

We expect that, under currently applicable accounting principles, the initial liability carrying amount of the notes will be the fair value of a similar debt instrument that does not have a conversion feature, valued using our cost of capital for similar, non-convertible debt. We expect to reflect the difference between the net proceeds from this offering and the initial liability carrying amount as a debt discount for accounting purposes, which will be amortized into interest expense over the term of the notes. As a result of this amortization, the interest expense that we expect to recognize for the notes for accounting purposes will be greater than the cash interest payments we will pay on the notes, which will result in lower reported income or higher reported loss. The lower reported income or higher reported loss resulting from this accounting treatment could depress the trading price of our common stock and the notes. However, on August 5, 2020, the Financial Accounting Standards Board published Accounting Standard Update No. 2020-06 (ASU 2020-06) that will eliminate the separate accounting for the debt and equity components as described above. The ASU will be effective for SEC-reporting entities for fiscal years beginning after December 15, 2021 (or, in the case of smaller reporting companies, December 15, 2023), including interim periods within those fiscal years. However, early adoption is permitted in certain circumstances for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. When effective, we expect the elimination of the separate accounting described above to reduce the interest expense that we expect to recognize for the notes for accounting purposes.

In addition, because we intend to settle conversions by paying the conversion value in cash up to the principal amount being converted and any excess in shares, under currently applicable accounting principles, we expect to be eligible to use the treasury stock method to reflect the shares underlying the notes in our diluted earnings

per share. Under this method, if the conversion value of the notes exceeds their principal amount for a reporting period, then we will calculate our diluted earnings per share assuming that all the notes were converted and that we issued shares of our common stock to settle the excess. However, if reflecting the notes in diluted earnings per share in this manner is anti-dilutive, or if the conversion value of the notes does not exceed their principal amount for a reporting period, then the shares underlying the notes will not be reflected in our diluted earnings per share. However, ASU 2020-06, when adopted by us, will eliminate the treasury stock method for convertible instruments such as the notes we are offering and instead require application of the “if-converted” method. Under that method, diluted earnings per share would generally be calculated assuming that all the notes were converted solely into shares of common stock at the beginning of the reporting period, unless the result would be anti-dilutive. The application of the if-converted method may reduce our reported diluted earnings per share.

Furthermore, if any of the conditions to the convertibility of the notes is satisfied, then we may be required under applicable accounting standards to reclassify the liability carrying value of the notes as a current, rather than a long-term, liability. This reclassification could be required even if no noteholders convert their notes and could materially reduce our reported working capital.

If a make-whole fundamental change occurs prior to the maturity date, we will under certain circumstances increase the conversion rate applicable to holders who convert their notes within a specified timeframe. The amount of the increase in the conversion rate depends on the date when the make-whole fundamental change becomes effective and the applicable price, as described in this prospectus supplement. See “Description of Notes—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change.”

Although the increase in the conversion rate is designed to compensate you for the lost option value of your notes as a result of the make-whole fundamental change, the increase in the conversion rate is only an approximation of the lost value and may not adequately compensate you for the loss. In addition, you will not be entitled to an increased conversion rate if the applicable price is greater than $100.00 per share of common stock or less than $4.81 per share of common stock (in each case, subject to adjustment).

Our obligation to increase the conversion rate as described above could also be considered a penalty, in which case its enforceability would be subject to general principles of reasonableness of economic remedies. In addition, we will not increase the conversion rate to an amount that exceeds 207.9002 shares of common stock per $1,000 principal amount of notes (subject to adjustment in the same manner as the conversion rate).

As adjusted to include the sale of the notes we are offering hereby and giving effect to the expected repurchase of our Existing Notes, the principal amount of our total consolidated long-term debt as of June 30, 2020 would have been approximately $428.0 million. The indenture for the notes will not restrict our ability to incur additional indebtedness.

Our level of indebtedness could have important consequences to you, because:

Our operations may not generate sufficient cash to enable us to service our debt. If we fail to make a payment on the notes, we could be in default on the notes, and this default could cause us to be in default on our other outstanding indebtedness. Conversely, a default on our other outstanding indebtedness may cause a default under the notes.

In the event the conditional conversion feature of the notes is triggered, holders of the notes will be entitled to convert the notes at any time during specified periods at their option. See “Description of Notes—Conditions for Conversion.” If one or more holders elect to convert their notes, unless we elect to satisfy our conversion obligation by delivering solely shares of our common stock (excluding cash in lieu of any fractional share), we would be required to settle a portion or all of our conversion obligation through the payment of cash, which could adversely affect our liquidity. In addition, even if holders do not elect to convert their notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal amount of the notes as a current, rather than long-term, liability, which would result in a material reduction of our net working capital.

The notes bear interest semi-annually at a rate of 6.75% per year. If a fundamental change occurs, then, subject to a limited exception described in this prospectus supplement, holders may require us to repurchase, for cash, all or any portion of their notes at 100% of their principal amount plus accrued and unpaid interest. In addition, upon conversion of the notes, unless we have elected to satisfy our conversion obligation by delivering solely shares of our common stock (excluding cash in lieu of any fractional share), we will be required to pay cash in respect of all or a portion of our conversion obligation. We may not have sufficient funds to pay the interest, repurchase price or cash in respect of our conversion obligation when due. If we fail to pay interest on the notes, repurchase the notes or pay any cash payment due upon conversion when required, we will be in default under the indenture governing the notes. See “Description of Notes—Interest Payments,” “Description of Notes—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and “Description of Notes—Events of Default.”

Prior to the close of business on the business day immediately preceding November 17, 2025, you may convert your notes only if specified conditions are met. If the specific conditions for conversion are not met, you will not be able to convert your notes until November 17, 2025 or thereafter. Therefore, you may not be able to realize the appreciation, if any, in the value of our common stock after the issuance of the notes in the offering and prior to such date. In addition, the inability to freely convert may also adversely affect the trading price of the notes and your ability to sell the notes.

The indenture for the notes does not:

Furthermore, the indenture for the notes contains only limited protections in the event of a change of control. We could engage in many types of transactions, such as acquisitions, refinancings or recapitalizations, that could substantially affect our capital structure and the value of the notes and our common stock but may not constitute a “fundamental change” that permits holders to require us to repurchase their notes or a “make-whole fundamental change” that permits holders to convert their notes at a potentially increased conversion rate. For these reasons, you should not consider the covenants in the indenture or the repurchase features of the notes as a significant factor in evaluating whether to invest in the notes.

The occurrence of certain “make-whole fundamental changes” as described under “Description of Notes—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change” or the occurrence of certain “fundamental changes” as described under “Description of Notes—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” pursuant to the terms of the notes, or certain other similar events, will require us to redeem our then outstanding Existing Notes.

Although the underwriters have indicated that they intend to make a market in the notes, they are not obligated to do so, and any of their market making activities may be terminated or limited at any time. In addition, although we have registered the offer and sale of the notes under the Securities Act, there can be no assurance as to the liquidity of markets for the notes, the ability of noteholders to sell their notes or the prices at which notes could be sold. The notes may trade at prices that are lower than their initial purchase price depending on many factors, including prevailing interest rates and the markets for similar securities. The liquidity of trading markets for the notes may also be adversely affected by general declines or disruptions in the markets for debt securities. Those market declines or disruptions could adversely affect the liquidity of and market for the notes independent of our financial performance or prospects. An active market for the notes may not exist or develop or, if developed, may not continue. In the absence of an active trading market, you may not be able to transfer the notes within the time or at the price you desire.

We expect to use approximately $10.5 million of the net proceeds from this offering to fund the cost of entering into the capped call transactions and the remainder of the net proceeds, together with cash on hand, to repurchase approximately $90 million aggregate principal amount of the outstanding 2022 Notes and approximately $95 million aggregate principal amount of the outstanding 2023 Notes, in each case in privately negotiated transactions concurrently with this offering. You may not agree with the ways we decide to use these proceeds, and our use of the proceeds may not yield any profits.

If a “fundamental change” occurs, holders of the notes will have the right, at their option, to require us to repurchase all or any portion of their notes. In the event of a “make-whole fundamental change,” we may be required to increase the conversion rate applicable to notes surrendered for conversion in connection with such make-whole fundamental change. In addition, the indenture for the notes prohibits us from engaging in certain mergers or acquisitions unless, among other things, the surviving entity assumes our obligations under the notes. Our existing convertible note indentures have similar provisions and under our Term Loan, a change of control (as defined therein) is an event of default.

Our articles of incorporation give our board of directors the authority, without any action by our shareholders, to fix the rights and preferences on up to 5,000,000 shares of undesignated preferred stock, including dividend, liquidation and voting rights. In addition, our by-laws divide our board of directors into three classes and our

directors may only be removed by a supermajority vote. We are also subject to certain anti-takeover provisions of the Minnesota Business Corporation Act. We also have employment arrangements with all of our executive officers that could require cash payments in the event of a “change of control.”

Any or all of the provisions or factors described above may discourage a takeover proposal or tender offer not approved by management and our board of directors, even if our shareholders may otherwise view the proposal or tender offer as favorable.

We do not intend to rate the notes, but if a rating agency rates the notes, it may assign a rating that is lower than the ratings expected by investors. Ratings agencies also may lower any rating on the notes in the future. If rating agencies assign a lower-than-expected rating or reduce, or indicate that they may reduce, their ratings in the future, the trading price of the notes could significantly decline.

We expect that many investors in the notes, including potential purchasers of the notes from investors in this offering, will seek to employ a convertible note arbitrage strategy. Under this strategy, investors typically short sell a certain number of shares of our common stock and adjust their short position over time while they continue to hold the notes. Investors may also implement this type of strategy by entering into swaps on our common stock in lieu of, or in addition to, short selling shares of our common stock.

The SEC and other regulatory authorities have implemented various rules and taken certain actions, and may in the future adopt additional rules and take other actions, that may impact those engaging in short selling activity involving equity securities (including our common stock). These rules and actions include Rule 201 of SEC Regulation SHO, the adoption by the Financial Industry Regulatory Authority, Inc., and the national securities exchanges of a “limit up-limit down” program, the imposition of market-wide circuit breakers that halt trading of securities for certain periods following specific market declines, and the implementation of certain regulatory reforms required by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. Any governmental or regulatory action that restricts investors’ ability to effect short sales of our common stock or enter into equity swaps on our common stock could depress the trading price of, and the liquidity of the market for, the notes.

In addition, the liquidity of the market for our common stock and other market conditions could deteriorate, which could reduce, or eliminate entirely, the number of shares available for lending in connection with short sale transactions and the number of counterparties willing to enter into an equity swap on our common stock with a note investor. These and other market events could make implementing a convertible note arbitrage strategy prohibitively expensive or infeasible. If investors in this offering or potential purchasers of the notes that seek to employ a convertible note arbitrage strategy are unable to do so on commercial terms, or at all, then the trading price of, and the liquidity of the market for, the notes may significantly decline.

We will have the right to redeem the notes, in whole or in part, in certain circumstances on or after August 15, 2023 (but, in the case of a partial redemption, no later than the 40th scheduled trading day immediately before the maturity date). See “Description of Notes—Optional Redemption.” If we redeem your notes, then you may not be entitled to benefit from potential future appreciation in the trading price of our common stock, and you may be unable to reinvest any proceeds from the redemption in comparable investments at favorable interest rates. In addition, a redemption of less than all of the outstanding notes will likely harm the liquidity of the market for the unredeemed notes following the redemption. Accordingly, if your notes are not redeemed in a partial redemption, then you may be unable to sell your notes at the times you desire or at favorable prices, if at all, and the trading price of your notes may decline.

We will generally have the right to settle conversions in cash, shares of our common stock or a combination of cash and shares. If we elect to settle conversions solely in cash or in a combination of cash and shares, then the consideration due upon conversion will be determined based on the volume-weighted average price of our

common stock during the related “observation period,” which is defined under the caption “Description of Notes—Settlement Upon Conversion” and will consist of 40 “VWAP trading days.” Except in certain circumstances, the observation period will begin after the related conversion date. Accordingly, a considerable amount of time may lapse between the time you elect to convert your notes and the time you receive the consideration due upon conversion, and if the trading price of our common stock declines during this time, then you may receive less consideration, or consideration that is less valuable, than expected.

If you hold notes, you will not, as such, be entitled to any rights with respect to our common stock (including, without limitation, voting rights and rights to receive any dividends or other distributions on our common stock), but you will be subject to all changes affecting our common stock. You will have the rights with respect to our common stock only if you convert your notes and become a record owner of common stock on the conversion date (in the case of physical settlement) or the last trading day of the applicable observation period (in the case of combination settlement), and only to the extent that we are obligated to deliver to you shares of common stock in respect of our conversion obligation. For example, in the event that an amendment is proposed to our articles of incorporation or bylaws requiring shareholder approval and the record date for determining the shareholders of record entitled to vote on the amendment occurs prior to the date you are deemed the record owner of our common stock, if any, due upon conversion, you will not be entitled to vote on the amendment, although you will nevertheless be subject to any changes in the powers, preferences or special rights of our common stock. In addition, because the notes may be settled by delivery of solely cash, you may not receive any shares upon conversion.

We currently intend to retain our earnings, if any, for the future operation and growth of our business. As a result, we do not anticipate paying cash dividends on our common stock in the foreseeable future. Because we do not anticipate paying cash dividends for the foreseeable future, holders who convert their notes and receive shares of our common stock will not realize a return on their investment unless the trading price of our common stock appreciates, which we cannot assure.

In connection with the pricing of the notes, we entered into capped call transactions with the option counterparties. The capped call transactions cover, subject to customary adjustments, the number of shares of common stock initially underlying the notes. The capped call transactions are expected generally to reduce the potential dilution of our common stock upon conversion of the notes or at our election (subject to certain conditions) offset any cash payments we are required to make in excess of the aggregate principal amount of converted notes, as the case may be, with such reduction or offset subject to a cap.

We have been advised that, in connection with establishing their initial hedges of the capped call transactions, the option counterparties or their respective affiliates expect to enter into cash-settled over-the-counter derivative transactions with respect to our common stock concurrently with or shortly after the pricing of the notes and may unwind these cash-settled over-the-counter derivative transactions and purchase shares of our common stock in open market transactions following the pricing of the notes. This activity could increase (or reduce the size of any decrease in) the market price of our common stock or the notes at that time.

In addition, the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding various derivatives with respect to our common stock and/or purchasing or selling our common stock or other securities of ours in secondary market transactions following the pricing of the notes and from time to time prior to the maturity of the notes (and are likely to do so on each exercise date of the capped call transactions, which are expected to occur during the 40 trading day period beginning on the 41st scheduled trading day prior to the maturity date of the notes, or following any termination of any portion of the capped call transactions in connection with any repurchase, exchange, redemption or conversion of the notes if we make the relevant election under the capped call transactions). This activity could also cause or avoid an increase or a decrease in the market price of our common stock or the notes, which could affect your

ability to convert the notes and, to the extent the activity occurs during any observation period related to a conversion of notes, it could affect the number of shares and value of the consideration that you will receive upon conversion of the notes.

In addition, if any such capped call transaction fails to become effective, whether or not this offering of notes is completed, the option counterparty party thereto may unwind its hedge positions with respect to our common stock, which could adversely affect the value of our common stock and, if the notes have been issued, the value of the notes.

The capped call transactions are separate transactions. As a holder of the notes, you will not have any rights with respect to the capped call transactions.

The option counterparties are financial institutions, and we will be subject to the risk that any or all of them might default under the capped call transactions. Our exposure to the credit risk of the option counterparties will not be secured by any collateral. Past global economic conditions have resulted in the actual or perceived failure or financial difficulties of many financial institutions. If an option counterparty becomes subject to insolvency proceedings, we will become an unsecured creditor in those proceedings with a claim equal to our exposure at that time under the capped call transactions with such option counterparty. Our exposure will depend on many factors but, generally, an increase in our exposure will be correlated to an increase in the market price subject to the cap and in the volatility of our common stock. In addition, upon a default by an option counterparty, we may suffer more dilution than we currently anticipate with respect to our common stock. We can provide no assurances as to the financial stability or viability of the option counterparties.

We expect to use approximately $183 million (or approximately $186 million with accrued interest) to repurchase approximately $90 million aggregate principal amount of the outstanding 2022 Notes and approximately $95 million aggregate principal amount of the outstanding 2023 Notes, in each case in privately negotiated transactions concurrently with this offering. The terms of any repurchases of the Existing Notes will depend on several factors, including the market price of Helix’s common stock and the trading price of the 2022 Notes and the 2023 Notes at the time of such repurchase(s). Any repurchase of our Existing Notes may affect the market price of our common stock. We also expect that holders of Existing Notes that sell such Existing Notes to us may enter into or unwind various derivatives with respect to our common stock and/or purchase or sell shares of our common stock in the market to hedge their exposure in connection with these transactions. In particular, we expect that many holders of the Existing Notes employ a convertible arbitrage strategy with respect to such Existing Notes and have a short position with respect to our common stock that they would close, through purchases of our common stock, in connection with our repurchase, if any, of their Existing Notes. This activity could increase (or reduce the size of any decrease in) the market price of our common stock or the notes offered hereby at that time, which could also impact the initial conversion prices of the notes offered hereby.

The conversion rate of the notes will be adjusted in certain circumstances, as described under “Description of Notes — Adjustments to the Conversion Rate,” “Description of Notes — Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” and “Description of Notes — Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change.” Adjustments (or failures to make adjustments) that are considered to have the effect of increasing the proportionate interest of a holder of a note in our assets or earnings and profits may in some circumstances result in a deemed distribution to the holder for U.S. federal income tax purposes, even though the holder has not received any cash or property as a result of such adjustments. Adjustments to the conversion rate made pursuant to a bona fide reasonable adjustment formula that have the effect of preventing the dilution of the interest of the holders of the notes, however, will generally not be considered to result in a deemed distribution. Certain of the possible conversion

rate adjustments provided in the notes (including, without limitation, adjustments in respect of taxable dividends to holders of our common stock and adjustments to the conversion rate upon a make-whole fundamental change) may not qualify as being pursuant to a bona fide reasonable adjustment formula. If such an adjustment is made and does not so qualify, a holder generally will be deemed to have received a distribution even if the holder does not receive any cash or property as a result of such adjustment. Any deemed distributions will be taxed in the same manner as an actual distribution, but may not be eligible for the reduced rates of tax applicable to the receipt of dividend income by certain non-corporate holders or the dividends-received deduction. With respect to a Non-U.S. Holder (as defined below in “Material U.S. Federal Income Tax Considerations”), such deemed distribution, to the extent treated as a dividend, generally will be subject to U.S. federal withholding tax (currently at a 30% rate, or such lower rate as may be specified by an applicable treaty as to which a Non-U.S. Holder has appropriately claimed the benefit). Such withholding tax (or any applicable backup withholding with respect to a deemed distribution) may be withheld from payments of interest and payments of cash or common stock upon conversion, repurchase or maturity of the notes or sales proceeds received by a holder, or if any withholding taxes (including backup withholding) are paid on behalf of a holder, those amounts may be set off against such payments of cash or common stock (or, in some circumstances, any payments on our common stock) or sales proceeds received by, or other funds or assets of, such holder. The Internal Revenue Service has proposed regulations addressing the amount and timing of deemed distributions, obligations of withholding agents and filing and notice obligations of issuers, which if adopted could affect the U.S. federal income tax treatment of beneficial owners of notes deemed to receive such a distribution. See “Material U.S. Federal Income Tax Considerations.”

Upon the conversion of a note into cash or a combination of both cash and our common stock, certain holders will generally be required to recognize gain on the conversion for U.S. federal income tax purposes. Prospective investors should carefully review the information regarding tax considerations relevant to an investment in the notes set forth under “Material U.S. Federal Income Tax Considerations” and are also urged to consult their own tax advisors prior to investing in the notes.

In certain circumstances, the conversion consideration may be changed. See “Description of Notes—Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales.” Depending on the circumstances at the time of such an event, such a change may result in a taxable event for U.S. federal income tax purposes. In addition, a subsequent conversion for the new conversion consideration may be a taxable event regardless of the chosen settlement method. See “Material U.S. Federal Income Tax Considerations.”

We will initially issue the notes in the form of one or more “global notes” registered in the name of Cede & Co., as nominee of DTC. Beneficial interests in global notes will be shown on, and transfers of global notes will be effected only through, the records maintained by DTC. Except in limited circumstances, we will not issue certificated notes. See “Description of Notes—Book-Entry Delivery and Form.” Accordingly, if you own a beneficial interest in a global note, then you will not be considered an owner or holder of the notes. Instead, DTC or its nominee will be the sole holder of the notes. Payments of principal, interest and other amounts on global notes will be made to the paying agent, who will remit the payments to DTC. We expect that DTC will then credit those payments to the DTC participant accounts that hold book-entry interests in the global notes and that those participants will credit the payments to indirect DTC participants. Unlike persons who have certificated notes registered in their names, owners of beneficial interests in global notes will not have the direct right to act on our solicitations for consents or requests for waivers or other actions from noteholders. Instead, those beneficial owners will be permitted to act only to the extent that they have received appropriate proxies to do so from DTC or, if applicable, a DTC participant. The applicable procedures for the granting of these proxies may not be sufficient to enable owners of beneficial interests in global notes to vote on any requested actions on a timely basis.

We estimate that our net proceeds from the sale of the notes will be approximately $192.5 million after deducting the underwriting fees and all estimated offering expenses that are payable by us.

In connection with the pricing of the notes, we entered into privately negotiated capped call transactions with the option counterparties, as described under “Description of the Concurrent Capped Call Transactions.” We intend to use approximately $10.5 million of the net proceeds from this offering to fund the cost of entering into the capped call transactions.

We expect to use approximately $183 million (or approximately $186 million with accrued interest), consisting of the remainder of the net proceeds from this offering, together with cash on hand, to repurchase approximately $90 million aggregate principal amount of the outstanding 2022 Notes and approximately $95 million aggregate principal amount of the outstanding 2023 Notes in privately negotiated transactions effected through one of the underwriters or its affiliate, as our agent, concurrently with this offering. These repurchases could have the effect of increasing, or limiting a decline in, the market price of our common stock concurrently with the pricing of the notes, and could result in a higher effective conversion price for the notes in this offering. See “Risk Factors—Risks Related to the Notes and the Underlying Shares of Common Stock—Repurchases of our 2022 Notes and 2023 Notes may affect the value of the notes and our common stock.”

As of August 10, 2020, we had outstanding $125.0 million principal amount of 2022 Notes and $125.0 million principal amount of 2023 Notes. The 2022 Notes mature on May 1, 2022, and interest on the 2022 Notes accrues at a rate of 4.25% per year. The 2023 Notes mature on September 15, 2023, and interest on the 2023 Notes accrues at a rate of 4.125% per year. For a more complete description of our indebtedness, including a more complete description of the 2022 Notes and the 2023 Notes, see “Description of Other Indebtedness” in this prospectus supplement.

We have never declared or paid cash dividends on our common stock and do not intend to pay cash dividends in the foreseeable future. We currently intend to retain earnings, if any, for the future operation and growth of our business. In addition, our financing arrangements restrict the payment of cash dividends on our common stock.

The following table presents our cash and cash equivalents and our capitalization as of June 30, 2020:

You should read this table in conjunction with, and this table is qualified in its entirety by reference to, the information contained in “Use of Proceeds” on page S-19 of this prospectus supplement, as well as our unaudited consolidated financial statements and the related notes included in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2020 filed with the SEC on July 24, 2020 and our other reports filed with the SEC that are incorporated by reference herein.

We will issue the notes pursuant to an indenture to be entered into on or about the date the notes are first issued (the “Base Indenture”) between us and The Bank of New York Mellon Trust Company, N.A., as trustee (the “trustee”), as amended and supplemented by a first supplemental indenture, to be entered into on or about the date the notes are first issued (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), between us and the trustee. The terms of the notes include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”).

The following summary of the terms of the notes and the Indenture does not purport to be complete and is subject, and qualified in its entirety by reference, to the detailed provisions of the notes and the Indenture. You should read carefully the section entitled “Description of Debt Securities” in the accompanying prospectus for a description of other material terms of the notes and the Indenture. However, to the extent the description of the notes in this section conflicts with any statements in the section entitled “Description of Debt Securities” in the accompanying prospectus, the description in this section will control.

You may request a copy of the Indenture (when executed) from us as described under “Where You Can Find More Information.”

For purposes of this summary, the terms “Helix,” “Company,” “we,” “us” and “our” refer only to Helix Energy Solutions Group, Inc. and not to any of its subsidiaries, unless we specify otherwise.

We are offering $200.0 million aggregate principal amount of our convertible senior notes due 2026 (the “notes”). The notes bear interest at a rate of 6.75% per annum payable semi-annually in arrears on February 15 and August 15 of each year, beginning on February 15, 2021, to holders of record at the close of business on the preceding February 1 and August 1, respectively, except as described below.

The notes we are offering:

The notes mature on February 15, 2026, unless earlier converted, redeemed or repurchased.

All cash payments on the notes will be made in U.S. dollars.

We will issue the notes in denominations of integral multiples of $1,000 principal amount, without coupons. We will initially issue the notes as global securities in book-entry form. We will make payments in respect of notes represented by global securities by wire transfer of immediately available funds to DTC or its nominee as registered owner of the global securities. We will make payments in respect of notes that are issued in certificated form by wire transfer of immediately available funds to the accounts specified by each holder of

more than $5.0 million aggregate principal amount of the notes. However, if a holder of a certificated note does not specify an account, or holds $5.0 million or less in aggregate principal amount of the notes, then we will mail a check to that holder’s registered address.

We may, from time to time, without notice to or the consent of the holders, reopen the Indenture under which the notes will be issued and issue additional notes in an unlimited aggregate principal amount with the same terms (subject to certain exceptions) as the notes offered hereby, in an unlimited aggregate principal amount, provided if the additional notes are not fungible with the notes offered hereby for United States federal income tax purposes, then they must be issued with a different CUSIP number. The notes offered hereby and any additional notes would be treated as a single class for all purposes under the Indenture and would vote together as one class on all matters with respect to the notes.

You may convert certificated notes at the office of the conversion agent, present certificated notes for registration of transfer at the office of the registrar for the notes and present certificated notes for payment at maturity at the office of the paying agent. We have appointed the trustee as the initial conversion agent, registrar and paying agent for the notes. We will not provide a sinking fund for the notes. The Indenture does not contain any financial covenants and will not limit our ability to incur additional indebtedness, including senior or secured indebtedness, pay dividends or issue or repurchase our securities. In addition, the Indenture does not provide any protection to holders of notes in the event of a highly leveraged transaction or a change in control, except as, and only to the limited extent, described under “—Conversion Rights—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change,” “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and “—Consolidation, Merger and Sale of Assets.”

If any interest payment date, maturity date, redemption date, repurchase date or settlement date (including upon the occurrence of a fundamental change, as described below) falls on a day that is not a business day, then the required payment will be made on the next succeeding business day with the same force and effect as if made on the date that the payment was due, and no additional interest will accrue on that payment for the period from and after the interest payment date, maturity date, redemption date or repurchase date (including upon the occurrence of a fundamental change, as described below), as the case may be, to that next succeeding business day. Solely for purposes of the immediately preceding sentence, a day on which the applicable place of payment is authorized or required by law or executive order to close or be closed will be deemed not to be a “business day.”

The provisions described in the accompanying prospectus under the captions “Description of Debt Securities—Form, Exchange, Registration and Transfer,” “—Payment and Paying Agent” and “—Book-Entry Debt Securities” will not apply to the notes and will be deemed to be replaced with the corresponding provisions described in this “Description of Notes” section.

The notes will be our general unsecured senior obligations and will rank equally in right of payment with all our other unsecured senior indebtedness. However, the notes will be effectively subordinated to any of our existing and future secured indebtedness and other obligations to the extent of the value of the assets securing the indebtedness or other obligations. Our obligations under our credit agreement are guaranteed by our domestic subsidiaries (except Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited (formerly known as Canyon Offshore Limited) and Helix Well Ops (UK) Limited, each wholly owned Scottish subsidiaries, and are secured by pledges or mortgages of (i) most of our assets, (ii) the shares of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited, and (iii) most of the assets of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited. In addition, we have pledged up to 66% of the shares of certain foreign subsidiaries to the lenders as additional security. See “Description of Other Indebtedness—Credit Agreement.” The notes will also be effectively subordinated to all liabilities, including trade payables and lease obligations, of our subsidiaries. Any right by us to receive the assets of any of our subsidiaries upon a liquidation or reorganization of that subsidiary, and the consequent right of the holders of the notes to participate in those assets, will be effectively subordinated to the claims of that subsidiary’s creditors, except to the extent that we are recognized as a creditor of such subsidiary, in which case our claims would still be effectively subordinated to any security interests in the assets of such subsidiary and subordinated to any indebtedness of such subsidiary that is senior to that held by us.

As of June 30, 2020, we had approximately $386.86 million of consolidated indebtedness outstanding, net of unamortized discounts and issuance costs, of which $258.95 million was indebtedness of Helix Energy Solutions Group, Inc., including $31.21 million of secured indebtedness, and $127.91 million of which was indebtedness of our subsidiaries.

Our subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay any amounts due on the notes or to make any funds available for payment on the notes, whether by dividends, loans or other payments. In addition, the payment of dividends and the making of loans and advances or other payments to us by our subsidiaries may be subject to statutory, regulatory, contractual or other restrictions, will depend on their earnings or financial condition and are subject to various business considerations. As a result, we may be unable to gain access to the cash flow or assets of our subsidiaries.

The Indenture does not limit the amount of additional indebtedness, including senior or secured indebtedness, which we can create, incur, assume or guarantee, nor does the Indenture limit the amount of indebtedness or other liabilities that our subsidiaries can create, incur, assume or guarantee.

We will pay interest on the notes at a rate of 6.75% per annum, payable semi-annually in arrears on each February 15 and August 15 of each year, beginning on February 15, 2021. Except as described below, we will pay interest that is due on an interest payment date to holders of record at the close of business on the preceding February 1 and August 1 (each, a “record date”), respectively. Interest will accrue on the notes from, and including, August 14, 2020 or from, and including, the last date in respect of which interest has been paid or provided for, as the case may be, to, but excluding, the next interest payment date or maturity date, as the case may be. We will pay interest on the notes on the basis of a 360-day year consisting of twelve 30-day months.

If notes are converted after the close of business on a record date but prior to the open of business on the next interest payment date, holders of such notes at the close of business on such record date will, on such interest payment date, receive the full amount of the accrued and unpaid interest payable on such notes on such interest payment date notwithstanding the conversion. However, a holder who surrenders a note for conversion after the close of business on a record date but prior to the open of business on the next interest payment date (whether or not the holder of record as of the close of business on such record date) must pay to the conversion agent, upon surrender, an amount equal to the full amount of accrued and unpaid interest payable on the corresponding interest payment date on the note so converted; provided that no such interest payment need be made to us:

If the conditions for conversion of the notes described under “—Conditions for Conversion” and “—Conversion Procedures” are satisfied, holders of notes may, subject to prior maturity or repurchase, convert their notes in integral multiples of $1,000 principal amount based on an initial conversion rate of 143.3795 shares of common stock per $1,000 principal amount of notes (which represents an initial conversion price of approximately $6.97 per share of common stock). The conversion rate, and thus the conversion price, will be subject to adjustment as described below. Except as described below, we will not make any payment or other adjustment on conversion with respect to any accrued interest, if any, on the notes, and we will not adjust the conversion rate to account for accrued and unpaid interest, if any. Instead, accrued interest, if any, will be deemed to be paid by the consideration received by the holder upon conversion. As a result, accrued interest, if any, is deemed to be paid in full rather than cancelled, extinguished or forfeited. Upon conversion of the notes into a combination of cash and shares of our common stock, accrued and unpaid interest, if any, will be deemed to be paid first out of the cash paid upon such conversion.

We will not issue fractional shares upon conversion of notes. Instead, we will pay cash in lieu of fractional shares based on the closing sale price (as defined below) of our common stock on the conversion date (in the case of physical settlement) or the volume-weighted average price per share of our common stock on the last trading day of the relevant observation period (as defined below) (in the case of combination settlement).

In certain circumstances, a holder must, upon conversion, pay interest if the conversion occurs after the close of business on a record date and prior to the open of business on the next interest payment date. See “—Interest Payments” above. A note for which a holder has delivered a fundamental change repurchase notice, as described below, requiring us to repurchase the note may be surrendered for conversion only if the holder withdraws the notice in accordance with the Indenture.

If we call a holder’s notes for redemption, the holder may convert the notes only until the close of business on the second business day prior to the redemption date unless we fail to pay the redemption price.

“Closing sale price” on any date means, as determined by us, the per share price of the referenced security on such date, determined (i) on the basis of the closing per share sale price (or if no closing per share sale price is reported, the average of the bid and ask prices per share or, if more than one in either case, the average of the average bid prices per share and the average ask prices per share) on such date on the principal U.S. national or regional securities exchange on which shares of the referenced security are listed; or (ii) if shares of the referenced security are not listed on a U.S. national or regional securities exchange, as reported by OTC Markets Group Inc. or a similar organization; provided, however, that in the absence of any such report or quotation, the closing sale price shall be the price determined by a nationally recognized independent investment banking firm retained by us for such purpose as most accurately reflecting the per share price that a fully informed buyer, acting on his own accord, would pay to a fully informed seller, acting on his own accord, in an arms-length transaction, for a share of the referenced security.

We may appoint any bid solicitation agent, and we may change such bid solicitation agent.

“Trading day” means, with respect to the referenced security, a day during which (i) trading in the referenced security generally occurs on the principal U.S. national or regional securities exchange on which the referenced security is then listed or, if the referenced security is not then listed on a U.S. national or regional securities exchange, on the principal other market on which the referenced security is then traded, and (ii) a “market disruption event” (as defined below) has not occurred; provided, however, that if the referenced security is not listed for trading or quotation on or by any exchange, bureau or other organization, “trading day” will mean any business day.

“Market disruption event” means, with respect to a referenced security on any date such reference security is listed for trading or quotation on or by any exchange, bureau or other organization, the occurrence or existence, during the one-half hour period ending at the scheduled close of trading on such date on the principal U.S. national or regional securities exchange or other market on which such referenced security is listed for trading or trades, of any material suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in such referenced security or in any options, contracts or futures contracts relating to such referenced security.

The notes will be convertible only during certain periods or in certain circumstances, which we describe below. If the notes become convertible, we will provide written notice to the trustee, the conversion agent and each holder, and we will publicly announce, through a reputable national newswire service, that the notes have become convertible, stating, among other things:

We will send the notice as soon as practicable, but in no event later than the open of business on the business day following the date the notes become convertible as a result of the event. Holders may surrender their notes for conversion only in the following circumstances:

Prior to November 17, 2025, holders may surrender their notes for conversion during any calendar quarter after the calendar quarter ending September 30, 2020 (and only during such calendar quarter), if the closing sale price of our common stock for each of 20 or more trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price of the notes (the “conversion trigger price”) in effect on each applicable trading day.

Our board of directors (or a committee thereof) will make appropriate adjustments to the closing sale price of our common stock, in its good faith determination, to account for any adjustment to the conversion rate that becomes effective, or any event requiring an adjustment to the conversion rate where the “ex-dividend date” of the event occurs, during the 30 consecutive trading day period described above.

Prior to November 17, 2025, holders may surrender their notes for conversion during the five consecutive business days immediately after any ten consecutive trading day period (we refer to this ten consecutive trading day period as the “note measurement period”) in which the trading price per $1,000 principal amount of the notes, as determined following a request by a holder of notes in accordance with the procedures described below, for each trading day in that note measurement period was equal to or less than 97% of the conversion value of the notes on such trading day. We refer to this condition as the “trading price condition.”

Solely for purposes of the trading price condition, the “conversion value” per $1,000 principal amount of notes on each trading day in the note measurement period is the product of the closing sale price of our common stock and the conversion rate of the notes in effect on that trading day.

The bid solicitation agent will have no obligation to determine the trading price of the notes unless we have requested it to do so, and we will have no obligation to make such request unless a holder of at least $1.0 million aggregate principal amount of notes provides us with written notice that includes reasonable evidence that the trading price per $1,000 principal amount of the notes would be equal to or less than 97% of the conversion value of the notes. At such time, we will instruct the bid solicitation agent to determine the trading price of the notes for each of the next ten trading days and on each succeeding trading day until the trading price condition is no longer satisfied.

The “trading price” of the notes on any date of determination (the “determination date”) means the average of the secondary market bid quotations obtained by the bid solicitation agent for $2.0 million aggregate principal amount of the notes at approximately 3:30 p.m., New York City time, on such determination date from three independent nationally recognized securities dealers we select; provided, however, that if:

provided, further, that if no bids are received for such determination date, then the trading price of the notes on any date of determination will be deemed to be less than 97% of the conversion value of the notes on such determination date.

If we call any or all of the notes for redemption, a holder may convert any of its notes at any time prior to the close of business on the second business day immediately prior to the redemption date, unless we fail to pay the redemption price. From and after that time, the right to convert such note on account of such redemption will expire, unless we fail to pay the related redemption price, in which case the holders of notes called for redemption may convert such notes called for redemption at any time until the redemption price has been paid or duly provided for.

If, prior to November 17, 2025, there occurs (1) a “fundamental change” (as described under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change”); a (2) “make-whole fundamental change” (as described under “—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change”) or (3) a “common stock change event” (as described under “—Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales,” other than, in the case of this clause (3), a transaction described in clause (1) under such caption that complies with our obligations described below under the caption “—Consolidation, Merger and Sale of Assets,” if applicable, and is not a fundamental change or make-whole fundamental change), in each case other than a merger or other business combination transaction that is effected solely to change our jurisdiction of incorporation and that does not constitute a fundamental change or a make-whole fundamental change, then a holder may surrender its notes for conversion at any time during the period that begins on, and includes, the effective date of the transaction and ends on, and includes, the 35th business day after the effective date of the transaction (or, if such transaction also constitutes a fundamental change (other than an “exempted fundamental change,” as defined below under the caption “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change”), until the close of business on the business day prior to the related fundamental change repurchase date). We will notify holders and the trustee of any such transaction no later than the actual effective date of such transaction. In addition, if the transaction is a “fundamental change,” then the notes may also be surrendered for repurchase as described below under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change.” Holders that convert their notes in connection with a “make-whole fundamental change” may in some circumstances also be entitled to an increased conversion rate. See “—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change.”

In addition, if we elect to:

then we must notify holders of the action or event at least 45 business days before the ex-dividend date for such distribution. Once we have given such notice, holders may surrender their notes for conversion at any time until the earlier of 5:00 p.m., New York City time, on the business day immediately preceding the ex-dividend date for such distribution and our announcement that such distribution will not take place, even if the notes are not otherwise convertible at such time. However, we will not be required to provide such notice, and holders will not have the right to convert their notes pursuant to the provision described in the preceding sentence on account of a distribution, if each holder participates, at the same time and upon the same terms as holders of our common stock and solely as a result of holding the notes, in such distribution without having to convert their notes as if such holder held a number of shares of common stock equal to the conversion rate in effect on the record date for such distribution multiplied by the principal amount (expressed in thousands) of notes held by such holder.

The notes may be surrendered for conversion at any time from, and including, November 17, 2025 to the close of business on the second scheduled trading day immediately preceding February 15, 2026, regardless of the foregoing conditions.

To convert its note into shares of our common stock, cash or a combination of cash and shares of our common stock, as the case may be, a holder of a certificated note must:

We will pay any documentary, stamp or similar issue or transfer tax or duty due on the issue and delivery of any shares of our common stock upon conversion, except any tax or duty that is due because the converting holder requests those shares to be registered in a name other than the holder’s name.

If a holder holds a beneficial interest in a global note, to convert such note, a holder must comply with the last two requirements listed above and comply with DTC’s procedures for converting a beneficial interest in a global note. The date a holder complies with these requirements is the “conversion date” under the Indenture. A holder receiving shares of our common stock upon conversion will not be entitled to any rights as a holder of our common stock, including, among other things, the right to vote, respond to tender offers and receive dividends and notices of shareholder meetings, until the close of business on the conversion date (in the case of physical settlement) or the close of business on the last VWAP trading day of the applicable observation period (in the case of combination settlement).

Upon conversion of the notes, in satisfaction of our conversion obligation, we will pay or deliver, as the case may be, to holders, at our election, (i) shares of our common stock, together with cash in lieu of any fractional share (which we refer to as “physical settlement”); (ii) cash (which we refer to as “cash settlement”); or (iii) a combination of cash and shares of our common stock, together with cash in lieu of any fractional share (which we refer to as “combination settlement”). As used in this prospectus supplement, “settlement method” means physical settlement, cash settlement or combination settlement, as applicable.

We will inform the holders through the trustee of the settlement method we choose to satisfy our obligation upon conversion (and the specified cash amount (as defined below), if applicable), as follows:

provided, however, that if we call any notes for redemption, then (i) we will specify in the related redemption notice the settlement method that will apply to all conversions with a conversion date that occurs on or after the date we send such redemption notice and before the related redemption date; and (ii) if the related redemption date is after the 45th scheduled trading day immediately preceding the maturity date, then such settlement method must be the same settlement method that applies to all conversions with a conversion date that occurs on or after the 45th scheduled trading day immediately preceding the maturity date. Except as provided in the preceding sentence, we must use the same settlement method for all conversions with a conversion date that occurs on the same day, but we will not be obligated to use the same settlement method for conversions with conversion dates that occur on different days.

If we fail to give any notice within the time periods described as to how we intend to settle, then we will be deemed to have elected the “default settlement method” (as defined below) to apply and such failure will not be deemed to be a default under the Indenture. If we elect “combination settlement” to apply but we fail to specify the specified cash amount, then the specified cash amount will be deemed to be $1,000 per $1,000 principal amount of notes.

The “default settlement method” means physical settlement. However, we may, from time to time, change the default settlement method, to any settlement method that we are then permitted to elect, by sending notice of the new default settlement method to the noteholders. In addition, we may, by notice to the noteholders, elect to irrevocably fix the settlement method, or to irrevocably elect combination settlement and eliminate a specified cash amount or range of specified cash amounts, in each case to apply to all note conversions with a conversion date that is on or after the date we send such notice. If we irrevocably elect combination settlement and eliminate a specified cash amount or range of specified cash amounts, then (i) we will simultaneously change the default settlement method, if needed, to combination settlement with a specified cash amount that is consistent with such irrevocable election; and (ii) we will continue to have the ability to elect the specified cash amount (to any specified cash amount that is consistent with such irrevocable election) for subsequent conversions in the manner, and within the time periods, described above. Notwithstanding the foregoing, no such change in the default settlement method or irrevocable election will affect any settlement method theretofore elected (or deemed to be elected) with respect to any note pursuant to the provisions described in this “—Settlement Upon Conversion” section. For the avoidance of doubt, such an irrevocable election, if made, will be effective without the need to amend the Indenture or the notes, including pursuant to the provisions described in the 12th bullet point of the second paragraph under the caption “—Amendment and Modification” below. However, we may nonetheless choose to execute such an amendment at our option.

If we change the default settlement method or irrevocably fix the settlement method pursuant to the provisions described above, then we will either post the default settlement method or fixed settlement method, as applicable, on our website or disclose the same in a current report on Form 8-K (or any successor form) that is filed with the SEC.

We currently intend to settle conversions through combination settlement with a specified cash amount of $1,000 per $1,000 principal amount of notes.

Upon surrender of your notes for conversion, we will deliver cash, shares of our common stock or a combination thereof as described below under “—Settlement Upon Conversion.”

Except as described below under the captions “—Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change—The Increase in the Conversion Rate,” “—Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” and “—Adjustments to the Conversion Rate,” we will pay or deliver, as applicable, the consideration due upon conversion as follows: (i) if cash settlement or combination settlement applies, on or before the second business day immediately after the last VWAP trading day of such observation period; and (ii) if physical settlement applies, on or before the second business day immediately after such conversion date (or, if such conversion date occurs after February 1, 2026, on the maturity date (or, if the maturity date is not a business day, the next business day)).

“Relevant exchange” means the NYSE or, if our common stock is not then listed on the NYSE, the principal U.S. national or regional securities exchange on which our common stock is listed for trading.

The amount of cash and number of shares of our common stock, as the case may be, due upon conversion will be as follows:

The “daily settlement amount” per $1,000 principal amount of notes to be converted will consist of the following for each of the 40 consecutive VWAP trading days in the relevant observation period:

“Specified cash amount” means, with respect to the conversion of a note to which combination settlement applies, the maximum cash amount per $1,000 principal amount of such note deliverable upon such conversion (excluding cash in lieu of any fractional share of common stock).

The “daily conversion value” means, for each of the 40 consecutive VWAP trading days in the observation period, one-40th of the product of (i) the conversion rate in effect on such VWAP trading day and (ii) the volume-weighted average price of our common stock on such VWAP trading day.

The “volume-weighted average price” of our common stock on any VWAP trading day means such price per share of our common stock as displayed on Bloomberg (or any successor service) page “HLX <equity> AQR” in respect of the period from the scheduled open of trading until the scheduled close of trading of the primary trading session on such VWAP trading day; or, if such price is not available, the volume-weighted average price means the market value per share of our common stock on such day as determined, using a volume-weighted average price method, by a nationally recognized independent investment banking firm retained for this purpose by us.

The “observation period” means:

“VWAP trading day” means a day on which (i) there is no VWAP market disruption event; and (ii) trading in our common stock generally occurs on the principal U.S. national or regional securities exchange on which our common stock is then listed or, if our common stock is not then listed on a U.S. national or regional securities exchange, on the principal other market on which our common stock is then traded. If our common stock is not so listed or traded, then “VWAP trading day” means a business day.

“VWAP market disruption event” means, with respect to any date, (i) the failure by the principal U.S. national or regional securities exchange on which our common stock is then listed, or, if our common stock is not then listed on a U.S. national or regional securities exchange, the principal other market on which our common stock is then traded, to open for trading during its regular trading session on such date; or (ii) the occurrence or existence, for more than one half hour period in the aggregate, of any suspension or limitation imposed on

trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in our common stock or in any options, contracts or futures contracts relating to our common stock, and such suspension or limitation occurs or exists at any time before 1:00 p.m., New York City time, on such date.

“Scheduled trading day” means a day that is scheduled to be a trading day on the primary United States national securities exchange or market on which our common stock is listed or admitted for trading. If our common stock is not so listed or admitted for trading, “scheduled trading day” means any business day.

The applicable conversion rate will be subject to adjustment, without duplication, upon the occurrence of any of the following events, except that we will not make any adjustment to the conversion rate if each holder of notes participates (other than in the case of a transaction described in clauses (1) or (5) below), at the same time and upon the same terms as holders of our common stock and solely as a result of holding the notes, in any of the transactions described below without having to convert such holder’s notes as if such holder held a number of shares of common stock equal to the conversion rate, multiplied by the principal amount (expressed in thousands) of notes held by such holder:

where,

Any adjustment made under this clause (1) shall become effective immediately after the open of business on the ex-dividend date for such dividend or distribution, or immediately after the open of business on the effective date for such share split or share combination, as the case may be. If any dividend or distribution of the type described in this clause (1) is declared but not so paid or made, or any share split or combination of the type described in this clause (1) is announced but the outstanding shares of our common stock are not split or combined, as the case may be, the conversion rate shall be immediately readjusted, effective as of the date our board of directors (or a committee thereof) determines not to pay such dividend or distribution, or not to split or combine the outstanding shares of our common stock, as the case may be, to the conversion rate that would then be in effect if such dividend, distribution, share split or share combination had not been declared or announced.

stock at a price per share less than the average of the closing sale prices of our common stock over the 10 consecutive trading-day period ending on, and including, the trading day immediately preceding the date such distribution is announced, the conversion rate will be increased based on the following formula:

CR1 = CR0 x OS0 + XOS0 + Y

where,

Any increase made under this clause (2) will be made successively whenever any such rights, options or warrants are distributed and shall become effective immediately after the open of business on the ex-dividend date for such distribution. To the extent that shares of common stock are not delivered after the expiration of such rights, options or warrants, the conversion rate shall be decreased to the conversion rate that would then be in effect had the increase with respect to the distribution of such rights, options or warrants been made on the basis of delivery of only the number of shares of common stock actually delivered. If such rights, options or warrants are not so distributed, the conversion rate shall be decreased to be the conversion rate that would then be in effect if such ex-dividend date for such distribution had not occurred.

For purposes of this clause (2) and the provisions described above under the caption “—Conditions for Conversion—Conversion upon the Occurrence of Certain Corporate Transactions,” in determining whether any rights, options or warrants entitle the holders thereof to subscribe for or purchase shares of our common stock at less than such average of the closing sale prices for the 10 consecutive trading-day period ending on, and including, the trading day immediately preceding the date such distribution is announced, and in determining the aggregate offering price of such shares of our common stock, there shall be taken into account any consideration received by us for such rights, options or warrants and any amount payable on exercise or conversion thereof, with the value of such consideration, if other than cash, to be determined by our board of directors (or a committee thereof).

then the conversion rate will be increased based on the following formula:

CR1 = CR0 x SPSP – FMV

where,

If “FMV” (as defined above) is equal to or greater than the “SP” (as defined above), then, in lieu of the foregoing increase, each holder of a note shall receive, for each $1,000 principal amount of notes it holds, at the same time and upon the same terms as holders of our common stock, the amount and kind of our capital stock, evidences of our indebtedness, other assets, securities, property, rights, options or warrants that such holder would have received as if such holder owned a number of shares of common stock equal to the conversion rate in effect on the record date for the distribution.

Any increase made under this clause (3)(a) will become effective immediately after the open of business on the ex-dividend date for such distribution. If such distribution is not so paid or made, the conversion rate shall be decreased to be the conversion rate that would then be in effect if such distribution had not been declared.

CR1 = CR0 x FMV + MPMP

where,

The adjustment to the conversion rate under the preceding paragraph will be determined as of the end of the spin-off valuation period but will be given effect immediately after the open of business on the ex-dividend date for the spin-off, with retroactive effect. If a note is converted and the conversion date (in the case of physical settlement) or any VWAP trading day of the applicable observation period (in the case of cash settlement or combination settlement) occurs during the spin-off valuation period, then, notwithstanding anything to the contrary, we will, if necessary, delay the settlement of such conversion until the second business day after the last day of the spin-off valuation period.

CR1 = CR0 x SPSP – C

where,

If “C” (as defined above) is equal to or greater than “SP” (as defined above), then, in lieu of the foregoing increase, each holder of a note shall receive, for each $1,000 principal amount of notes, at the same time and upon the same terms as holders of our common stock, the amount of cash that such holder would have received as if such holder owned a number of shares of our common stock equal to the conversion rate on the record date for such cash dividend or distribution. Such increase shall become effective immediately after the open of business on the ex-dividend date for such dividend or distribution. If such dividend or distribution is not so paid, the conversion rate shall be decreased, effective as of the date our board of directors (or a committee thereof) determines not to make or pay such dividend or distribution, to be the conversion rate that would then be in effect if such dividend or distribution had not been declared.

CR1 = CR0 x AC + (SP x OS1)OS0 x SP

where,

The adjustment to the conversion rate pursuant to this clause (5) will be determined as of the end of the tender/exchange offer valuation period but will be given effect immediately after the expiration time, with retroactive effect. If a note is converted and the conversion date (in the case of physical settlement) or any VWAP trading day of the applicable observation period (in the case of cash settlement or combination settlement) occurs during the tender/exchange offer valuation period, then, notwithstanding anything to the contrary, we will, if necessary, delay the settlement of such conversion until the second business day after the last day of the tender/exchange offer valuation period.

Notwithstanding anything to the contrary, if:

then, solely for purposes of such conversion, we will, without duplication, give effect to such adjustment on such conversion date (in the case of physical settlement) or such VWAP trading day (in the case of combination settlement). In such case, if the date we are otherwise required to deliver the consideration due upon such conversion is before the first date on which the amount of such adjustment can be determined, then we will (i) deliver, on such date we are otherwise required by the Indenture, the consideration due upon such conversion based on the applicable unadjusted conversion rate(s); and (ii) deliver, on the business day immediately after such first date, any additional consideration arising from giving effect to such adjustment to the applicable conversion rate(s).

Notwithstanding anything to the contrary in the Indenture or the notes, if:

then (x) such conversion rate adjustment will not be given effect for such conversion (in the case of physical settlement) or for such VWAP trading day (in the case of combination settlement); and (y) the shares of common stock, if any, issuable upon such conversion (in the case of physical settlement) or issuable with respect to such VWAP trading day (in the case of combination settlement) based on such unadjusted conversion rate will be entitled to participate in such dividend or distribution.

The “ex-dividend date” is the first date on which our common stock trades on the applicable exchange or in the applicable market, regular way, without the right to receive the issuance, dividend or distribution in question from us or, if applicable, from the seller of our common stock on such exchange or market (in the form of due bills or otherwise) as determined by such exchange or market.

As used in this section titled “—Adjustments to the Conversion Rate,” “record date” means, with respect to any dividend, distribution or other transaction or event in which the holders of our common stock have the right to receive any cash, securities or other property, the date fixed for determination of holders of stock entitled to receive such cash, securities or other property (whether such date is fixed by our board of directors or a committee thereof or by statute, contract or otherwise).

The Indenture does not require us to adjust the conversion rate for any of the transactions described in the clauses (1) through (5) above (other than for share splits or share combinations) if we make provision for each holder of the notes to participate in the transaction, at the same time as holders of our common stock participate, without conversion, as if such holder held a number of shares of our common stock equal to the conversion rate in effect on the record date or effective date, as the case may be, for such transaction, multiplied by the principal amount (expressed in thousands) of notes held by such holder.

If we issue rights, options or warrants that are only exercisable upon the occurrence of certain triggering events, then:

We will not adjust the conversion rate pursuant to the provisions described in clauses (1) through (5), inclusive, above unless the adjustment would result in a change of at least 1% in the then effective conversion rate. However, we will carry forward any adjustment that we would otherwise have to make and take that adjustment into account in any subsequent adjustment. However, all such deferred adjustments must be given effect immediately upon the earliest of the following: (i) when all such deferred adjustments would result in a change of at least 1% to the conversion rate; (ii) the conversion date of, or any VWAP trading day of an observation period for, any note; (iii) the date a fundamental change or make-whole fundamental change occurs; (iv) the date we call any notes for redemption; and (iv) November 17, 2025. The provisions described in this paragraph are referred to herein as the “1% provision.”

Adjustments to the conversion rate will be calculated to the nearest 1/10,000th.

To the extent permitted by law and the continued listing requirements of the NYSE, we may, from time to time, increase the conversion rate by any amount for a period of at least 20 business days or any longer period permitted or required by law, so long as the increase is irrevocable during that period and our board of directors (or a committee thereof) determines that the increase is in our best interests. We will send a notice of the increase to the trustee, the conversion agent and the holders no later than the first day on which the increase commences. In addition, we may, but are not obligated to, increase the conversion rate as we determine to be advisable in order to avoid or diminish taxes to recipients of certain distributions.

To the extent that any future shareholder rights plan (i.e., a poison pill) adopted by us, is in effect, upon conversion of the notes, you will receive, in addition to any shares of our common stock that are otherwise due upon conversion, the rights under such future shareholder rights plan in respect of such shares of common stock, unless the rights have separated from our common stock at the time of conversion in accordance with the provisions of the applicable shareholder rights plan, in which case the conversion rate will be adjusted at the time of separation as if we had distributed to all holders of our common stock, shares of our capital stock, evidences of indebtedness, other assets, securities or property as described in clause (3)(a) under “—Adjustments to the Conversion Rate” above, subject to readjustment in the event of the expiration, termination or redemption of such rights. We currently do not have a shareholder rights plan.

In the event of an adjustment or the non-occurrence of an adjustment to the conversion rate, the holders of the notes may, in certain circumstances, be deemed to have received a distribution subject to U.S. federal income tax as a dividend. This generally would occur, for example, if we adjust the conversion rate to compensate holders for cash dividends on our common stock and could also occur if we make other distributions of cash or property to our shareholders. Any applicable withholding taxes (including backup withholding) with respect to deemed dividends may be withheld from payments of interest and payments of cash or common stock upon conversion, repurchase or maturity of the notes or sales proceeds received by a holder, or if any withholding taxes (including backup withholding) are paid on behalf of a holder, those amounts may be set off against such payments of cash or common stock (or, in some circumstances, any payments on our common stock) or sales proceeds received by, or other funds or assets of, such holder. See “Material U.S. Federal Income Tax Considerations.”

The conversion rate will not be adjusted:

If we:

in each case pursuant to which our common stock would be converted into or exchanged for, or would constitute solely the right to receive, cash, securities or other property, including any combination thereof (such an event, a “common stock change event,” and such cash, securities or property, the “reference property,” and the amount and kind of reference property that a holder of one share of our common stock would be entitled to receive on account of such common stock change event (without giving effect to any arrangement not to issue or deliver a fractional portion of any security or other property), a “reference property unit”), then, notwithstanding anything to the contrary,

If the common stock change event causes our common stock to be converted into, or exchanged for, the right to receive more than a single type of consideration (determined based in part upon any form of shareholder election), then the composition of the reference property unit will be deemed to be the weighted average of the types and amounts of consideration actually received by the holders of our common stock. We will notify holders of the weighted average as soon as practicable after such determination is made. We will agree in the Indenture not to become a party to any such common stock change event unless its terms are consistent with the foregoing.

A change in the conversion right such as this could substantially lessen or eliminate the value of the conversion right. For example, if a third party acquires us in a cash merger, each note would be convertible solely into cash and would no longer be potentially convertible into securities whose value could increase depending on our future financial performance, prospects and other factors. There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether the provisions above would apply to a sale, transfer, lease, conveyance or other disposition of less than all of our consolidated property or assets.

For a discussion of certain tax considerations applicable to a holder upon a change in the conversion right, see “Material U.S. Federal Income Tax Considerations.”

If, prior to the maturity date, there occurs any event or transaction (a “make-whole fundamental change”) that constitutes a “fundamental change” as defined below under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and determined after giving effect to any exceptions to or exclusions

from such definition (including, for the avoidance of doubt, after giving effect to the provision described in the proviso immediately after clause (3) of the definition of “change of control”), but excluding the “non-ownership change of control” exception, then, as described below under “—The Increase in the Conversion Rate,” we will increase the conversion rate applicable to notes that are converted with a conversion date that occurs at any time from, and including, the effective date of the make-whole fundamental change to, and including, the 35th business day after the effective date of the make-whole fundamental change (or, if the make-whole fundamental change also constitutes a fundamental change (other than an exempted fundamental change), as described under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change,” to the close of business on the business day prior to the fundamental change repurchase date for that fundamental change). We refer to this period as the “make-whole conversion period.”

We will send to the trustee, the conversion agent and the holders notice of the effective date of any make-whole fundamental change in accordance with the procedures described above under the caption “—Conditions for Conversion—Conversion upon the Occurrence of Certain Corporate Transactions.”

In connection with the make-whole fundamental change, we will increase the conversion rate by reference to the table below, based on the date when the make-whole fundamental change becomes effective, which we refer to as the “effective date,” and the “applicable price” (as defined below). If the make-whole fundamental change is a transaction or series of related transactions described in clause (3) of the definition of “change of control” as defined below under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change,” and the consideration (excluding cash payments for fractional shares or pursuant to statutory dissenters’ or appraisal rights) for shares of our common stock in the make-whole fundamental change consists solely of cash, then the “applicable price” will be the cash amount paid per share of our common stock in the make-whole fundamental change. In all other cases, the “applicable price” will be the average of the closing sale prices of our common stock for the five consecutive trading days immediately preceding, but excluding, the relevant effective date. Our board of directors (or a committee thereof) will make appropriate adjustments, in its good faith determination, to account for any adjustment to the conversion rate that becomes effective, or any event requiring an adjustment to the conversion rate where the “ex-dividend date” of the event occurs, at any time during those five consecutive trading days.

Upon surrender of notes for conversion in connection with a make-whole fundamental change, we will, at our option, satisfy our conversion obligation by delivering or paying, as the case may be, shares of our common stock (together with cash in lieu of any fractional share), cash or a combination of cash and shares of our common stock (together with cash in lieu of any fractional share) as described under “—Settlement Elections.” However, if the consideration for our common stock in any make-whole fundamental change is comprised entirely of cash, then, for any conversion of notes with a conversion date occurring on or after the effective date of such make-whole fundamental change, the conversion obligation will be calculated based solely on the applicable price for the transaction and will be deemed to be an amount, per $1,000 principal amount of converted notes, equal to the applicable conversion rate (including any adjustment as described in this section), multiplied by such applicable price. In such event, the cash due upon conversion will be determined and paid to holders in cash on the second business day following such conversion date.

The following table sets forth the number of additional shares per $1,000 principal amount of notes that will be added to the conversion rate applicable to the notes that are converted during the make-whole conversion period. The increased conversion rate will be used to determine the consideration due upon conversion, as described under “—Settlement Upon Conversion” above. If an event occurs that requires an adjustment to the conversion rate, we will, on the date we must adjust the conversion rate, adjust each applicable price set forth in the first column of the table below at the same time the conversion rate is so adjusted by multiplying the applicable price in effect immediately before the adjustment by a fraction:

In addition, we will adjust the number of additional shares in the table below at the same time, in the same manner in which, and for the same events for which, we must adjust the conversion rate as described under “—Adjustments to the Conversion Rate.”

The exact applicable price and effective date may not be as set forth in the table above, in which case:

However, we will not increase the conversion rate as described above to the extent the increase will cause the conversion rate to exceed 207.9002 shares of our common stock per $1,000 principal amount of notes. We will adjust this maximum conversion rate in the same manner in which, and for the same events for which, we must adjust the conversion rate as described under “—Adjustments to the Conversion Rate.”

Our obligation to increase the conversion rate as described above could be considered a penalty, in which case its enforceability would be subject to general principles of reasonableness of economic remedies.

Prior to August 15, 2023, the notes will not be redeemable. We may, at our option, redeem (a “conversion price trigger redemption”) some or all of the notes on a redemption date that occurs on or after August 15, 2023 (but, in the case of a partial redemption, no later than the 40th scheduled trading day immediately before the maturity date) if the closing sale price of our common stock has been at least 130% of the conversion price then in effect on (x) the trading day immediately preceding the date on which we provide a redemption notice and (y) for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide such redemption notice. The redemption price for each $1,000 principal amount of notes to be redeemed (the “conversion price trigger redemption price”) shall be payable in cash and shall be equal to the sum of (i) 100% of the principal amount of the notes to be redeemed, plus (ii) accrued and unpaid interest, if any, to, but excluding, the redemption date, plus (iii) the make-whole premium (as defined below). We must make these make-whole premium payments on all notes called for redemption prior to February 15, 2026, including notes subject to redemption that are converted after the date we delivered the notice of redemption.

The “make-whole premium” means, in respect of any notes called for a conversion price trigger redemption, the amount equal to the present value of the remaining scheduled payments of interest that would have been made on such notes to be redeemed had such notes remained outstanding from the relevant redemption date to, and including, February 15, 2026 (excluding interest accrued to, but excluding, such redemption date, which shall otherwise be payable pursuant to clause (ii) of the definition of conversion price trigger redemption price set forth above), with such present value of the remaining interest payments computed using a discount rate per annum equal to the reference discount rate (as defined below) plus 50 basis points.

The “reference discount rate” means, in respect of any make-whole premium, the yield to maturity of United States Treasury securities with a constant maturity (as compiled and published in the most recent Federal Reserve Statistical Release H.15 (519) that has become publicly available at least two business days prior to the relevant redemption date (or, if such Statistical Release is no longer published, any publicly available source of

similar market data)) most nearly equal to the period from such redemption date to the maturity date; provided, however, that if the period from such redemption date to the maturity date is less than one year, the weekly average yield on actively traded United States Treasury securities adjusted to a constant maturity of one year will be used. Any such reference discount rate shall be obtained by us.

If the redemption date occurs after a record date and on or prior to the immediately succeeding interest payment date, (i) accrued and unpaid interest shall be paid on such interest payment date to the record holder on the relevant record date, (ii) the redemption price will not include any accrued and unpaid interest, and (iii) the make-whole premium shall equal the present value of all remaining scheduled payments of interest on such notes, starting with the next interest payment date for which interest has not been provided for (but otherwise calculated as described in the definition of make-whole premium). The trustee shall have no duty to determine or calculate the make-whole premium, which shall be determined by us in accordance with the provisions of the Indenture, and the trustee shall not be under any responsibility to determine the correctness of any such determination and/or calculation and may conclusively rely on the correctness thereof.

We will provide notice of redemption to each holder of notes to be redeemed at least 45, but no more than 65, scheduled trading days before the related redemption date. If the redemption notice is given and funds are deposited as required, then interest will cease to accrue on and after the redemption date on those notes or portions of notes called for redemption (other than as described in clause (i) of the immediately preceding paragraph).

Once we have called the notes for redemption, notes or portions of notes will be convertible by the holder until the close of business on the second business day prior to the redemption date, unless we fail to pay the redemption price.

If we decide to redeem fewer than all of the outstanding notes, then, subject to applicable DTC rules, the trustee will select the notes to be redeemed (in principal amounts of $1,000 or integral multiples thereof) by lot, on a pro rata basis or by another method the trustee considers fair and appropriate in accordance with industry standards at the time of such redemption. If the trustee selects a portion of a holder’s notes for partial redemption and the holder converts a portion of its notes, the converted portion will be deemed to be from the portion selected for redemption.

We may not redeem any notes if the principal amount of the notes has been accelerated and such acceleration has not been rescinded on or before the redemption date (including as a result of the payment of the related redemption price and any related interest described above on the redemption date).

If a “fundamental change,” as described below, occurs, each holder will have the right, at its option, subject to the terms and conditions of the Indenture, to require us to repurchase for cash all or any portion of the holder’s notes in integral multiples of $1,000 principal amount, at a price (the “fundamental change repurchase price”) equal to 100% of the principal amount of the notes to be repurchased, plus, except as described below, any accrued and unpaid interest, if any, to, but excluding, the “fundamental change repurchase date,” as described below. However, if the fundamental change repurchase date is after a record date for the payment of an installment of interest and on or before the related interest payment date, then the full amount of interest due on that interest payment date will be payable, on that interest payment date, to the holder of record at the close of business on the record date, and the fundamental change repurchase price will not include any accrued and unpaid interest.

We must repurchase the notes on a date of our choosing, which we refer to as the “fundamental change repurchase date.” However, the fundamental change repurchase date shall be no later than 35 days, and no earlier than 20 days, after the date we send the relevant fundamental change notice, as described below.

Within 20 business days after the occurrence of a fundamental change, we must send to all holders of notes, and to beneficial owners as required by applicable law, a notice (the “fundamental change notice”) regarding the fundamental change. The fundamental change notice must state, among other things:

To exercise the fundamental change repurchase right with respect to any certificated notes, a holder must deliver the notes to be repurchased, duly endorsed for transfer, together with a written fundamental change repurchase notice to the paying agent no later than the close of business on the second business day immediately preceding the fundamental change repurchase date. This written notice must state:

A holder may withdraw any fundamental change repurchase notice by delivering to the paying agent a written notice of withdrawal prior to the close of business on the second business day immediately preceding the fundamental change repurchase date. The notice of withdrawal must state:

If the notes are not in certificated form, the above notices must instead comply with appropriate DTC procedures no later than the close of business on the second business day immediately preceding the fundamental change repurchase date.

We will pay the fundamental change repurchase price no later than the later of the fundamental change repurchase date and the time of book-entry transfer or delivery of the note, together with necessary endorsements.

For a discussion of certain tax considerations applicable to a holder upon the exercise of the repurchase right, see “Material U.S. Federal Income Tax Considerations.”

If the paying agent holds on the fundamental change repurchase date money sufficient to pay the fundamental change repurchase price due on all notes surrendered for repurchase in accordance with the terms of the Indenture, then, on and after the fundamental change repurchase date, such notes will cease to be outstanding and (except as described in the last sentence of the first paragraph under this “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” section) interest on such notes will cease to accrue, whether or not the book-entry transfer of the notes is made or whether or not the holder delivers the notes to the paying agent. Thereafter, all other rights of the relevant holders terminate, other than the right to receive the fundamental change repurchase price upon book-entry transfer or delivery of the note (and, if applicable, the right to receive interest).

A “fundamental change” will be deemed to occur upon the occurrence of a “change of control” or a “termination of trading.”

A “change of control” generally will be deemed to occur at such time as:

provided, however, that a transaction or event described in clauses (1) or (2) above will not constitute a change of control (and for the avoidance of doubt, we are not required to deliver the notice incidental thereto) if at least 90% of the consideration received or to be received by the holders of our common stock (excluding cash payments for fractional shares or pursuant to statutory dissenters’ or appraisal rights), in connection with such transaction or event, consists of common equity listed (or depositary receipts representing common equity, which depositary receipts are listed) on any of The New York Stock Exchange, The NASDAQ Global Market or The NASDAQ Global Select Market (or any of their respective successors), or that will be so listed when issued or exchanged in connection with such transaction or event, and such transaction or event constitutes a common stock change event whose reference property consists of such consideration.

For the purposes of this definition, any transaction or event described in both clause (1) and in clause (2)(i) or (2)(ii) above (disregarding the non-ownership change of control provision) will be deemed to occur solely pursuant to clause (2) above (subject to the non-ownership change of control provision).

There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether a transfer, lease, conveyance or other disposition of less than all of our consolidated property or assets would permit a holder to exercise its right to have us repurchase its notes in accordance with the fundamental change provisions described above.

A “termination of trading” is deemed to occur if shares of our common stock are not listed for trading on NYSE, The NASDAQ Global Select Market or The NASDAQ Global Market (or any of their respective successors).

The trustee shall have no duty to determine whether a fundamental change (or any component thereof) shall have occurred.

We may not have the financial resources, and we may not be able to arrange for financing, to pay the fundamental change repurchase price for all notes holders have elected to have us repurchase. Furthermore, the terms of our existing or future indebtedness may limit our ability to pay the repurchase price to repurchase notes. Our failure to repurchase the notes when required would result in an event of default with respect to the notes. The exercise by holders of the notes of their right to require us to repurchase their notes upon a fundamental change could cause a default under our other outstanding indebtedness, even if the fundamental change itself does not.

Furthermore, holders may not be entitled to require us to repurchase their notes in certain circumstances involving a significant change in the composition of our board of directors that does not occur in connection with a transaction that otherwise constitutes a fundamental change.

We may in the future enter into transactions, including recapitalizations, that would not constitute a fundamental change but that would increase our debt or otherwise adversely affect holders. The Indenture for the notes does not restrict our or our subsidiaries’ ability to incur indebtedness, including senior or secured indebtedness. Our incurrence of additional indebtedness could adversely affect our ability to service our indebtedness, including the notes.

In addition, the fundamental change repurchase feature of the notes would not necessarily afford holders of the notes protection in the event of highly leveraged or other transactions involving us that may adversely affect holders of the notes. Furthermore, the fundamental change repurchase feature of the notes may in certain circumstances deter or discourage a third party from acquiring us, even if the acquisition may be beneficial to you.

In connection with any fundamental change offer, we will, to the extent applicable:

Notwithstanding anything to the contrary herein, to the extent that compliance with this “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” would result in a violation of any federal or state securities laws or other applicable laws or regulations, we will comply with the applicable securities laws and regulations and will not be deemed to have breached our obligations by virtue of the conflict.

Notwithstanding anything to the contrary, we will be deemed to satisfy our obligations to repurchase notes pursuant to the provisions described above if (i) one or more third parties conduct the repurchase offer and repurchase tendered notes in a manner that would have satisfied our obligations to do the same if conducted directly by us; and (ii) an owner of a beneficial interest in any note repurchased by such third party or parties will not receive a lesser amount (as a result of taxes or for any other reason) than such owner would have received had we repurchased such note.

In addition, notwithstanding anything to the contrary, we will not be required to send a fundamental change notice, or offer to repurchase, or repurchase, any notes, as described above, in connection with a fundamental change occurring pursuant to clause (2)(b) (or pursuant to clause (1) that also constitutes a fundamental change occurring pursuant to clause (2)(b)) of the definition of “change of control,” if:

We refer to any fundamental change with respect to which, in accordance with the provisions described in the preceding paragraph, we do not offer to repurchase any notes as an “exempted fundamental change.”

No notes may be repurchased by us at the option of the holders upon a fundamental change if the principal amount of the notes has been accelerated and such acceleration has not been rescinded on or before the fundamental change repurchase date (including as a result of the payment of the related fundamental change repurchase price and any related interest described above on the fundamental change repurchase date).

For purposes of the notes, the description below under this section titled “—Consolidation, Merger and Sale of Assets” supersedes, in its entirety, the information in the accompanying prospectus under the caption “Description of Debt Securities—Consolidation, Merger and Sale of Assets.”

The Indenture prohibits us from consolidating with, or merging with or into, or selling, transferring, leasing, conveying or otherwise disposing of all or substantially all of our consolidated property or assets to, another person, whether in a single transaction or series of related transactions, unless, among other things:

When the successor assumes all of our obligations under an Indenture, except in the case of a lease, our obligations under the Indenture will terminate.

Some of the transactions described above could constitute a fundamental change that permits holders to require us to repurchase their notes, as described under “—Holders May Require Us to Repurchase their Notes Upon A Fundamental Change.”

There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether the provisions above would apply to a sale, transfer, lease, conveyance or other disposition of less than all of our consolidated property or assets.

For purposes of the notes, the description below under this section titled “—Events of Default” supersedes, in its entirety, the information in the accompanying prospectus under the caption “Description of Debt Securities—Events of Default.”

The following constitute defaults under the Indenture, subject to any additional limitations and qualifications included in the Indenture:

The foregoing will constitute events of default whatever the reason for any such event of default and whether it is voluntary or involuntary or is effected by operation of law or pursuant to any judgment, decree or order of any court or any order, rule or regulation of any administrative or governmental body.

If a default under the Indenture occurs and is continuing and is known to the trustee as provided for in the Indenture, the trustee must send to each holder of the notes notice of the default within 90 days after it occurs. The trustee may withhold notice to the holders of the notes of a default (except defaults in the payment of the principal of or interest on the notes) if the trustee considers it to be in the interest of the holders of the notes to withhold this notice.

If an event of default (other than an event of default relating to certain events of bankruptcy, insolvency or reorganization of us) occurs and continues, the trustee or the holders of at least 25% in principal amount of the outstanding notes may declare the principal and accrued and unpaid interest on the outstanding notes to be immediately due and payable. In case of certain events of bankruptcy, insolvency or reorganization involving us (and not solely involving one or more of our significant subsidiaries), the principal and accrued and unpaid interest on the notes will automatically become immediately due and payable. Under certain circumstances, the holders of a majority in principal amount of the outstanding notes may rescind such acceleration with respect to the notes and, as is discussed below, waive these past defaults.

The holders of a majority in principal amount of the then outstanding notes will have the right to direct in writing the time, method and place of any proceedings for any remedy available to the trustee or of exercising any trust or power conferred on the trustee, subject to limitations specified in the Indenture. The trustee, however, may refuse to follow any direction that conflicts with law or the Indenture or that the trustee determines may be unduly prejudicial to the rights of any other holder of the notes (it being understood that the trustee shall be under no obligation to make any such determination) or that may involve the trustee in personal liability, provided that the trustee may take any other action deemed proper by the trustee that is not inconsistent with that direction. Prior to taking any action under the Indenture, the trustee will be entitled to indemnification and/or security satisfactory to it in its sole discretion from holders directing the trustee against all losses and expenses caused by taking or not taking such action.

The holders of a majority in principal amount of outstanding notes may, by notice to the trustee, waive any past defaults under the Indenture, except a default due to the non-payment of principal or interest, if any, a failure to convert any notes into common stock when required pursuant to the terms of the Indenture, a default arising from our failure to redeem or repurchase any notes when required pursuant to the terms of the Indenture or a default in respect of any covenant that cannot be amended without the consent of each holder affected.

No holder of the notes may pursue any remedy under the Indenture, except in the case of a default due to the non-payment of principal or interest, on the notes, unless:

The Indenture requires us (i) every year to deliver to the trustee a statement as to performance of our obligations under the Indenture and as to any default and (ii) to deliver to the trustee prompt notice of any default.

A default in the payment of the notes, or a default with respect to the notes that causes them to be accelerated, may give rise to a cross-default under our existing borrowing arrangements.

Notwithstanding anything to the contrary described above, we may elect that the sole remedy for any event of default (a “reporting event of default”) pursuant to clause (5) above arising from our failure to comply with our obligations described below under the caption “—Exchange Act Reports” will, for each of the first 180 calendar days on which a reporting event of default has occurred and is continuing, consist exclusively of the accrual of special interest on the notes. If we have made such an election, then (i) the notes will be subject to acceleration as described above on account of the relevant reporting event of default from, and including, the 181st calendar day on which a reporting event of default has occurred and is continuing or if we fail to pay any accrued and unpaid special interest when due; and (ii) special interest will cease to accrue on any notes from, and including, such 181st calendar day.

Any special interest that accrues on a note will be payable on the same dates and in the same manner as the stated interest on such note and will accrue at a rate per annum equal to 0.25% of the principal amount thereof. For the avoidance of doubt, any special interest that accrues on a note will be in addition to the stated interest that accrues on such note. Each reference in this “Description of Notes” section to interest on any note includes special interest, if any, that has accrued on such note, unless the context requires otherwise.

To make the election to pay special interest as described above, we must provide notice of such election to noteholders before the date on which each reporting event of default first occurs. The notice will also, among other things, briefly describe the periods during which and rate at which special interest will accrue and the circumstances under which the notes will be subject to acceleration on account of such reporting event of default.

We will send to the trustee copies of all reports, information and documents that we are required to file with the SEC pursuant to Section 13(a) or 15(d) of the Exchange Act within 15 calendar days after the date that we are required to so file the same (after giving effect to all applicable grace periods under the Exchange Act). However, we need not send to the trustee any material for which we have received, or are seeking in good faith and have not been denied, confidential treatment by the SEC. Each report that we file with the SEC through the EDGAR system, provided we notify the trustee in the manner provided in the Indenture of each such filing and the location thereof in reasonable detail, will be deemed to have been delivered to the trustee.

For purposes of the notes, the description below under this section titled “—Amendment and Modification” supersedes, in its entirety, the information in the accompanying prospectus under the caption “Description of Debt Securities—Modification and Waiver.”

The consent of the holders of a majority in principal amount of the outstanding notes is required to modify or amend the Indenture. However, a modification or amendment requires the consent of the holder of each outstanding note affected by such modification or amendment if it would:

However, notwithstanding anything to the contrary described above, we and the trustee may modify certain provisions of the Indenture or the notes without the consent of the holders of the notes, including to:

The holders of a majority in aggregate principal amount of the outstanding notes may, on behalf of all the holders of all notes, waive all compliance by us with provisions in the Indenture, as detailed in the Indenture (other than the provisions of the Indenture whose modification or amendment otherwise requires the consent of the holder of each outstanding note affected by such modification or amendment as described above); or waive any past default or event of default under the Indenture and its consequences, except a default or event of default in the payment of any amount due, or in the obligation to deliver consideration upon conversion or with respect to any note or in respect of any provision which under the Indenture cannot be modified or amended without the consent of the holder of each outstanding note affected.

For purposes of the notes, the description below under this section titled “—Satisfaction and Discharge” supersedes, in its entirety, the information in the accompanying prospectus under the caption “Description of Debt Securities—Discharge and Defeasance.”

We may satisfy and discharge our obligations under the Indenture by delivering to the trustee for cancellation all outstanding notes or by depositing with the trustee or delivering to the holders, as applicable, after all then-outstanding notes have become due and payable, whether at the stated maturity, or any redemption date or fundamental change repurchase date, or upon conversion or otherwise, cash (or, if applicable with respect to any conversion shares of our common stock or other reference property) sufficient to pay all of the outstanding notes and paying all other sums payable under the Indenture by us. Such discharge is subject to terms contained in the Indenture.

We will be responsible for making all calculations called for under the notes. These calculations include, but are not limited to, determinations of the market prices of our common stock, the amount of accrued interest payable on the notes, the closing sale prices, the volume-weighted average prices, the conversion price of the notes, any conversion values, daily settlement amounts and the conversion rates of the notes, including adjustments to any of the foregoing required by the Indenture. We will make all these calculations in good faith, and, absent manifest error, our calculations will be final and binding on holders of notes. We will provide a schedule of our calculations to each of the trustee and the conversion agent, and each of the trustee and the conversion agent is entitled to rely upon the accuracy of our calculations without independent verification. The trustee will forward our calculations to any holder of notes upon the request of that holder.

None of our past, present or future directors, officers, employees or shareholders, as such, will have any liability for any of our obligations under the notes or the Indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a note, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the notes. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

If money deposited with the trustee or paying agent for the payment of principal of, or accrued and unpaid interest on, the notes remains unclaimed for two years, the trustee and paying agent will pay the money back to us upon our written request. However, the trustee and paying agent have the right to withhold paying the money back to us until they publish (in no event later than five days after we request repayment) in a newspaper of general circulation in the City of New York, or send to each holder, a notice stating that the money will be paid back to us if unclaimed after a date no less than 30 days from the publication or sending, in each case at our cost. After the trustee or paying agent pays the money back to us, holders of notes entitled to the money must look to us for payment as general creditors, subject to applicable law, and all liability of the trustee and the paying agent with respect to the money will cease.

We will replace mutilated, lost, destroyed or stolen notes at the holder’s expense upon delivery to the trustee of the mutilated notes or evidence of the loss, destruction or theft of the notes satisfactory to the trustee and us. In the case of a lost, destroyed or stolen note, we or the trustee may require, at the expense of the holder, indemnity (including in the form of a bond) satisfactory to us and the trustee.

The Bank of New York Mellon Trust Company, N.A. will act as the trustee under the Indenture. We have appointed The Bank of New York Mellon Trust Company, N.A. as paying agent, conversion agent, note registrar and custodian for the notes. The trustee or its affiliates may also provide banking and other services to us in the ordinary course of their business.

The transfer agent for our common stock is EQ Shareowner Services.

We do not intend to apply for listing of the notes on any securities exchange or to arrange for their quotation on any interdealer quotation system. Our common stock is listed on NYSE under the ticker symbol “HLX.”

The notes offered hereby will be issued in registered, global form in denominations of integral multiples of $1,000 principal amount. The notes will be issued on the issue date therefor only against payment in immediately available funds.

The notes offered hereby initially will be represented by one or more permanent global certificates in definitive, fully registered form without interest coupons, which we refer to as the “global securities.”

The global securities will be deposited upon issuance with the trustee as custodian for DTC in New York, New York, and registered in the name of DTC or its nominee for credit to an account of a direct or indirect participant in DTC (including the Euroclear Bank S.A./N.V. (“Euroclear”) or Clearstream Banking, société anonyme (“Clearstream”)), as described below under “—Depositary Procedures.”

Except as set forth below, the global securities may be transferred, in whole and not in part, only to DTC, to another nominee of DTC or to a successor of DTC or its nominee. Beneficial interests in the global securities may not be exchanged for notes in certificated form except in the limited circumstances described below under “—Exchange of Book-Entry Securities for Certificated Securities.”

Transfers of beneficial interests in the global securities will be subject to the applicable rules and procedures of DTC and its direct or indirect participants (including, if applicable, those of Euroclear and Clearstream), which may change from time to time.

The following description of the operations and procedures of DTC, Euroclear and Clearstream is provided solely as a matter of convenience. These operations and procedures are solely within the control of the respective settlement systems and are subject to changes by them. We take no responsibility for these operations and procedures and urge investors to contact the systems or their participants directly to discuss these matters.

DTC is a limited-purpose trust company created to hold securities for its participating organizations, referred to as “participants,” and facilitate the clearance and settlement of transactions in those securities between DTC’s participants through electronic book-entry changes in accounts of its participants. DTC’s participants include securities brokers and dealers (including the underwriters), banks, trust companies, clearing corporations and certain other organizations. Access to DTC’s system is also available to other entities such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a DTC participant, either directly or indirectly, which entities are referred to as “indirect participants.” Persons who are not DTC participants may beneficially own securities held by or on behalf of DTC only through participants or indirect participants. DTC has no knowledge of the identity of beneficial owners of securities held by or on behalf of DTC. DTC’s records reflect only the identity of its participants to whose accounts securities are credited. The ownership interests and transfer of ownership interests of each beneficial owner of each security held by or on behalf of DTC are recorded on the records of DTC’s participants and indirect participants.

Pursuant to procedures established by DTC:

Investors in the global securities may hold their interests therein directly through DTC, if they are participants in such system, or indirectly through organizations (including Euroclear and Clearstream) that are participants or indirect participants in such system. Euroclear and Clearstream will hold interests in the notes on behalf of their participants through customers’ securities accounts in their respective names on the books of their respective depositaries. The depositaries, in turn, will hold interests in the notes in customers’ securities accounts in the depositaries’ names on the books of DTC.

All interests in a global security, including those held through Euroclear or Clearstream, will be subject to the procedures and requirements of DTC. Those interests held through Euroclear or Clearstream will also be subject to the procedures and requirements of these systems. The laws of some jurisdictions require that certain persons take physical delivery of certificates evidencing securities they own. Consequently, the ability to transfer beneficial interests in a global security to such persons will be limited to that extent. Because DTC can act only on behalf of its participants, which in turn act on behalf of indirect participants, the ability of beneficial owners of interests in a global security to pledge such interests to persons or entities that do not participate in the DTC system, or otherwise take actions in respect of such interests, may be affected by the lack of a physical certificate evidencing such interests. For certain other restrictions on the transferability of the notes, see “—Exchange of Book-Entry Securities for Certificated Securities.”

Except as described below, owners of interests in the global security will not have notes registered in their names, will not receive physical delivery of notes in certificated form and will not be considered the registered owners or holders thereof under the Indenture for any purpose. All references herein to “holders” refers to the registered holders of the notes.

Payments in respect of the principal of, and interest on, a global security registered in the name of DTC or its nominee will be payable by the trustee (or the paying agent if other than the trustee) to DTC in its capacity as the registered holder under the Indenture. We and the trustee will treat the persons in whose names the notes, including the global securities, are registered as the owners thereof for the purpose of receiving such payments and for any and all other purposes whatsoever. Consequently, neither we nor the trustee or any of our respective agents has or will have any responsibility or liability for:

DTC has advised us that its current practice, upon receipt of any payment in respect of securities such as the notes (including principal and interest), is to credit the accounts of the relevant participants with the payment on the payment date in amounts proportionate to their respective holdings in the principal amount of the

relevant security as shown on the records of DTC, unless DTC has reason to believe it will not receive payment on such payment date. Payments by the participants and the indirect participants to the beneficial owners of notes will be governed by standing instructions and customary practices and will be the responsibility of the participants or the indirect participants and will not be the responsibility of DTC, the trustee or us. Neither we nor the trustee will be liable for any delay by DTC or any of its participants in identifying the beneficial owners of the notes, and we and the trustee may conclusively rely on and will be protected in relying on instructions from DTC or its nominee for all purposes.

Transfers between participants in DTC will be effected in accordance with DTC’s procedures, and will be settled in same day funds, and transfers between participants in Euroclear and Clearstream will be effected in accordance with their respective rules and operating procedures.

Cross-market transfers between participants in DTC, on the one hand, and Euroclear or Clearstream participants, on the other hand, will be effected through DTC in accordance with DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by their depositaries. Cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in that system in accordance with the rules and procedures and within the established deadlines (Brussels time) of that system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its respective depositaries to take action to effect final settlement on its behalf by delivering or receiving interests in the relevant global security in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Euroclear and Clearstream participants may not deliver instructions directly to the depositaries for Euroclear or Clearstream.

Because of time zone differences, the securities account of a Euroclear or Clearstream participant purchasing an interest in a global security from a participant in DTC will be credited and reported to the relevant Euroclear or Clearstream participant during the securities settlement processing day (which must be a business day for Euroclear and Clearstream) immediately following the settlement date of DTC. DTC has advised us that cash received in Euroclear or Clearstream as a result of sales of interests in a global security by or through a Euroclear or Clearstream participant to a participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.

DTC has advised us that it will take any action permitted to be taken by a holder of notes only at the direction of one or more participants to whose account with DTC interests in the global securities are credited and only in respect of such portion of the aggregate principal amount of the notes as to which such participant or participants has or have given such direction.

Although DTC, Euroclear and Clearstream have agreed to the foregoing procedures to facilitate transfers of interests in the global securities among participants in DTC, Euroclear and Clearstream, they are under no obligation to perform or to continue to perform such procedures, and the procedures may be discontinued at any time. None of us, any underwriter or the trustee will have any responsibility for the performance by DTC, Euroclear or Clearstream or their respective participants or indirect participants of their respective obligations under the rules and procedures governing their operations.

The information in this section concerning DTC, Euroclear and Clearstream and their book-entry systems has been obtained from sources that we believe to be reliable, but neither we nor any underwriter takes any responsibility for the accuracy thereof.

The global securities are exchangeable for certificated securities in definitive, fully registered form without interest coupons only if:

The Indenture and the notes will be governed by and construed in accordance with the laws of the State of New York.

In connection with the pricing of the notes, we entered into capped call transactions with the option counterparties. The capped call transactions will cover, subject to customary anti-dilution adjustments, the number of shares of our common stock underlying the notes. We intend to use approximately $10.5 million of the net proceeds from this offering to pay the cost of the capped call transactions.

The capped call transactions are expected generally to reduce the potential dilution to our common stock upon conversion of the notes or at our election (subject to certain conditions) offset any cash payments we are required to make in excess of the aggregate principal amount of converted notes, as the case may be, in the event that the market price per share of our common stock, as measured under the terms of the capped call transactions, is greater than the strike price of the capped call transactions, which initially corresponds to the conversion price of the notes and is subject to customary anti-dilution adjustments that may not match those applicable to the conversion price. If, however, the market price per share of our common stock, as measured under the terms of the capped call transactions, exceeds the cap price of the capped call transactions, there would nevertheless be dilution or there would not be an offset of such potential cash payments, in each case, to the extent that such market price exceeds the cap price of the capped call transactions.

We will not be required to make any cash payments or any share deliveries to the option counterparties or their respective affiliates upon the exercise of the options that are a part of the capped call transactions, but we will be entitled to receive from them a number of shares of our common stock, or at our election (subject to certain conditions) an amount of cash, generally based on the amount by which the market price per share of our common stock, as measured under the terms of the capped call transactions, exceeds the strike price of the capped call transactions during the relevant valuation period under the capped call transactions. However, if the market price per share of our common stock, as measured under the terms of the capped call transactions, exceeds the cap price of the capped call transactions during such valuation period, the number of shares of common stock or the amount of cash we expect to receive upon exercise of the capped call transactions will be capped based on the amount by which the cap price exceeds the strike price of the capped call transactions.

Additionally, if the conversion price of the notes does not equal the strike price of the capped call transactions due to an adjustment or adjustments made during the term of the capped call transactions to the conversion price of the notes and/or the strike price of the capped call transactions, to the extent that the market price per share of our common stock exceeds the conversion price of the notes but does not exceed the strike price of the capped call transactions at any time of expiration, we will not be entitled to receive any shares of our common stock or cash under the capped call transactions upon such expiration.

The cap price of the capped call transactions will initially be 75% above the closing price of our common stock on the NYSE on the date of this prospectus supplement and is subject to certain adjustments under the terms of the capped call transactions.

The capped call transactions are separate transactions that we entered into with the option counterparties, are not part of the terms of the notes and will not change the holders’ rights under the notes. As a holder of the notes, you will not have any rights with respect to the capped call transactions.

For a discussion of the potential impact of any market or other activity by the option counterparties or their respective affiliates in connection with these capped call transactions, see “Underwriting—Capped Call Transactions” and “Risk Factors—Risks Related to the Notes and the Underlying Shares of Common Stock—The capped call transactions may affect the value of the notes and our common stock.”

The following is a summary of certain of our indebtedness that will be outstanding following the consummation of this offering. The summary below does not purport to be complete and is qualified in its entirety by reference to the applicable documents, copies of which have been filed with the SEC and which we will provide you upon request. See the sections entitled “Where You Can Find More Information.”

On June 30, 2017, we entered into an Amended and Restated Credit Agreement (together with the amendments made thereafter, collectively the “Credit Agreement”) with a group of lenders led by Bank of America, N.A. (“Bank of America”). On June 28, 2019, we amended our existing term loan (the “Term Loan”) and revolving credit facility (the “Revolving Credit Facility”) under the Credit Agreement. The Credit Agreement provides for a $35 million Term Loan and a $175 million Revolving Credit Facility and matures on December 31, 2021. The Revolving Credit Facility permits us to obtain letters of credit up to a sublimit of $25 million. Pursuant to the Credit Agreement, subject to existing lender participation and/or the participation of new lenders, and subject to standard conditions precedent, we may request an increase in the commitments under the Revolving Credit Facility by an amount of up to $100 million. As of June 30, 2020, we had no borrowings under the Revolving Credit Facility, and our available borrowing capacity under that facility, based on the leverage ratios, totaled $172.4 million, net of $2.6 million of letters of credit issued under that facility. As of June 30, 2020, we had $31.1 million of borrowings outstanding under our Term Loan.

Our obligations under our credit agreement are guaranteed by our domestic subsidiaries (except Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited (formerly known as Canyon Offshore Limited) and Helix Well Ops (UK) Limited, each wholly owned Scottish subsidiaries, and are secured by pledges or mortgages of (i) most of our assets, (ii) the shares of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited, and (iii) most of the assets of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.), and Helix Robotics Solutions Limited and Helix Well Ops (UK) Limited. In addition, these obligations are secured by pledges of up to 66% of the shares of certain foreign subsidiaries.

Borrowings under the Credit Agreement bear interest, at our election, at either Bank of America’s base rate, the LIBOR or a comparable successor rate, or a combination thereof. The Term Loan bears interest at a rate per annum equal to (i) in the case of base rate loans, Bank of America’s base rate plus a margin of 2.25% and (ii) in the case of LIBOR rate loans, the LIBOR or a comparable successor rate selected by us plus a margin of 3.25%. The interest rate on the Term Loan was 3.43% as of June 30, 2020. Borrowings under the Revolving Credit Facility bear interest at a rate per annum equal to (i) in the case of base rate borrowings, Bank of America’s base rate plus a margin ranging from 1.50% to 2.50% and (ii) in the case of LIBOR rate borrowings, the LIBOR or a comparable successor rate selected by us plus a margin ranging from 2.50% to 3.50%. A letter of credit fee is payable by us equal to the applicable margin for LIBOR rate loans multiplied by the daily amount available to be drawn under the applicable letter of credit. Margins on borrowings under the Revolving Credit Facility will vary based on our Consolidated Total Leverage Ratio (as defined below) as provided for in the Credit Agreement. We also pay a fixed commitment fee of 0.50% per annum on the unused portion of the Revolving Credit Facility.

The Term Loan principal is required to be repaid in quarterly installments of 2.5% of the aggregate principal amount of the Term Loan, with a balloon payment at maturity. Installment amounts are subject to adjustment for any prepayments on the Term Loan. We may prepay indebtedness outstanding under the Term Loan without premium or penalty, but may not reborrow any amounts prepaid. We may prepay indebtedness outstanding under the Revolving Credit Facility without premium or penalty, and may reborrow any amounts prepaid up to the amount available under the Revolving Credit Facility.

The Credit Agreement and the other documents entered into in connection with the Credit Agreement include terms and conditions, including covenants, which we consider customary for this type of transaction. The covenants include certain restrictions on our and certain of our subsidiaries’ ability to grant liens, incur indebtedness, make investments, merge or consolidate, sell or transfer assets, pay dividends and make capital expenditures. In addition, the Credit Agreement obligates us to maintain: (i) a consolidated interest coverage

ratio, measured as of the end of any fiscal quarter, of no less than 2.50 to 1.00; (ii) a consolidated secured leverage ratio, measured at any time during any period of four fiscal quarters, of no greater than 2.50 to 1.00; and (iii) a consolidated total leverage ratio, measured at any time during any period of four fiscal quarters, of no greater than 3.50 to 1.00.

We may designate one or more of our new foreign subsidiaries as subsidiaries not generally subject to the covenants in the Credit Agreement (the “Unrestricted Subsidiaries”). The debt and EBITDA of the Unrestricted Subsidiaries, with the exception of Helix Q5000 Holdings, S.à r.l. (“Q5000 Holdings”), a wholly owned Luxembourg subsidiary of Helix Vessel Finance S.à r.l., are not included in the calculations of our financial covenants. In June 2019, in connection with the amendment of the Credit Agreement we wrote off the remaining unamortized debt issuance costs associated with a lender exiting the Credit Agreement. As of June 30, 2020, we were in compliance with the applicable covenants and ratios under the Credit Agreement.

On November 1, 2016, we completed a public offering and sale of the 2022 Notes in the aggregate principal amount of $125 million. The 2022 Notes bear interest at a rate of 4.25% per annum and are payable semi-annually in arrears on November 1 and May 1 of each year, beginning on May 1, 2017. The 2022 Notes mature on May 1, 2022 unless earlier converted, redeemed or repurchased. During certain periods and subject to certain conditions, the 2022 Notes are convertible by the holders into shares of our common stock at an initial conversion rate of 71.9748 shares of our common stock per $1,000 principal amount (which represents an initial conversion price of approximately $13.89 per share of common stock), subject to adjustment in certain circumstances. We have the right and the intention to settle the principal amount of any such future conversions in cash.

Prior to November 1, 2019, the 2022 Notes were not redeemable. Beginning November 1, 2019, if certain conditions are met, we may redeem all or any portion of the 2022 Notes at a redemption price payable in cash equal to 100% of the principal amount to be redeemed plus accrued and unpaid interest and a “make-whole premium” (as defined in the indenture governing the 2022 Notes). Holders of the 2022 Notes may require us to repurchase the notes following a “fundamental change” (as defined in the indenture governing the 2022 Notes).

The indenture governing the 2022 Notes contains customary terms and covenants, including that upon certain events of default occurring and continuing, either the trustee under the indenture or the holders of not less than 25% in aggregate principal amount then outstanding under the 2022 Notes may declare the entire principal amount of all the notes, and the interest accrued on such notes, if any, to be immediately due and payable. In the case of certain events of bankruptcy, insolvency or reorganization relating to us or a subsidiary, the principal amount of the 2022 Notes together with any accrued and unpaid interest thereon will become immediately due and payable.

The 2022 Notes are accounted for by separating between the equity component of $11.0 million recognized in shareholders’ equity and the debt component which is presented as long-term debt, net of unamortized debt discount and debt issuance costs. The effective interest rate for the 2022 Notes is 7.3% after considering the effect of the accretion of the related debt discount over the term of the 2022 Notes. For the three- and six-month periods ended June 30, 2020, interest expense (including amortization of the debt discount) related to the 2022 Notes totaled $2.1 million and $4.3 million, respectively. For the three- and six-month periods ended June 30, 2019, interest expense (including amortization of the debt discount) related to the 2022 Notes totaled $2.1 million and $4.2 million, respectively. The remaining unamortized debt discount of the 2022 Notes was $6.4 million at June 30, 2020 and $8.0 million at December 31, 2019.

We expect to use approximately $90 million of the net proceeds from this offering, together with cash on hand, to repurchase a portion of the outstanding 2022 Notes in privately negotiated transactions concurrently with this offering. This prospectus supplement does not constitute an offer to purchase or the solicitation of an offer to sell the 2022 Notes. As of June 30, 2020, we were with the applicable covenants under the indenture governing the 2022 Notes.

On March 20, 2018, we completed a public offering and sale of the 2023 Notes in the aggregate principal amount of $125 million. The 2023 Notes bear interest at a rate of 4.125% per annum and are payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2018. The 2023 Notes mature on September 15, 2023 unless earlier converted, redeemed or repurchased. During certain periods and subject to certain conditions, the 2023 Notes are convertible by the holders into shares of our common stock at an initial conversion rate of 105.6133 shares of our common stock per $1,000 principal amount (which represents an initial conversion price of approximately $9.47 per share of common stock), subject to adjustment in certain circumstances. We have the right and the intention to settle the principal amount of any such future conversions in cash.

Prior to March 15, 2021, the 2023 Notes were not redeemable. On or after March 15, 2021, if certain conditions are met, we may redeem all or any portion of the 2023 Notes at a redemption price payable in cash equal to 100% of the principal amount to be redeemed plus accrued and unpaid interest and a “make-whole premium” (as defined in the indenture governing the 2023 Notes). Holders of the 2023 Notes may require us to repurchase the notes following a “fundamental change” (as defined in the indenture governing the 2023 Notes).

The indenture governing the 2023 Notes contains customary terms and covenants, including that upon certain events of default occurring and continuing, either the trustee under the indenture or the holders of not less than 25% in aggregate principal amount then outstanding under the 2023 Notes may declare the entire principal amount of all the notes, and the interest accrued on such notes, if any, to be immediately due and payable. In the case of certain events of bankruptcy, insolvency or reorganization relating to us or a significant subsidiary, the principal amount of the 2023 Notes together with any accrued and unpaid interest thereon will become immediately due and payable.

The 2023 Notes are accounted for by separating between the equity component of $15.9 million recognized in shareholders’ equity and the debt component which is presented as long-term debt, net of unamortized debt discount and debt issuance costs. The effective interest rate for the 2023 Notes is 7.8% after considering the effect of the accretion of the related debt discount over the term of the 2023 Notes. For the three- and six-month periods ended June 30, 2020, interest expense (including amortization of the debt discount) related to the 2023 Notes totaled $2.2 million and $4.3 million, respectively. For the three- and six-month periods ended June 30, 2019, interest expense (including amortization of the debt discount) related to the 2023 Notes totaled $2.1 million and $4.2 million, respectively. The remaining unamortized debt discount of the 2023 Notes was $12.8 million at June 30, 2020 and $14.5 million at December 31, 2019.

We expect to use approximately $95 million of the net proceeds from this offering, together with cash on hand, to repurchase a portion of the outstanding 2023 Notes in privately negotiated transactions concurrently with this offering. This prospectus supplement does not constitute an offer to purchase or the solicitation of an offer to sell the 2023 Notes. As of June 30, 2020, we were with the applicable covenants under the indenture governing the 2023 Notes.

This U.S. government guaranteed financing (the “MARAD Debt”), pursuant to Title XI of the Merchant Marine Act of 1936 administered by the Maritime Administration, was used to finance the construction of the Q4000. The MARAD Debt is collateralized by the Q4000 and is guaranteed 50% by us. The MARAD Debt is payable in equal semi-annual installments, matures in February 2027 and bears interest at a rate of 4.93%.

In September 2014, Q5000 Holdings entered into a credit agreement (the “Nordea Credit Agreement”) with a syndicated bank lending group for a term loan (the “Nordea Q5000 Loan”) in an amount of up to $250 million. The Nordea Q5000 Loan was funded in the amount of $250 million in April 2015 at the time the Q5000 was delivered to us. Helix Vessel Finance S.à r.l., a direct wholly owned Luxembourg subsidiary of Helix, guaranteed the Nordea Q5000 Loan. The loan is secured by the Q5000 and its charter earnings as well as by a pledge of the shares of Q5000 Holdings. This indebtedness is non-recourse to Helix.

We amended the Nordea Q5000 Loan on March 11, 2020. Prior to the amendment, the Nordea Q5000 Loan accrued interest at the LIBOR rate plus a margin of 2.5% and was repayable in scheduled quarterly principal

installments of $8.9 million with a balloon payment of $80.4 million on April 30, 2020. The amendment increased the margin to 2.75%, maintained the existing quarterly amortization requirements, and extended the final maturity to January 31, 2021 with a balloon payment on that date of $53.6 million. The remaining principal balance and unamortized debt issuance costs related to the Nordea Q5000 Loan are classified as current in the accompanying condensed consolidated balance sheets. We may elect to prepay indebtedness outstanding under the Nordea Q5000 Loan without premium or penalty, but may not reborrow any amounts prepaid. Quarterly principal installments are subject to adjustment for any prepayments on this debt.

The Nordea Credit Agreement and related loan documents include terms and conditions, including covenants and prepayment requirements, that we consider customary for this type of transaction. The covenants include restrictions on Q5000 Holdings’ ability to grant liens, incur indebtedness, make investments, merge or consolidate, sell or transfer assets, and pay dividends. In addition, the Nordea Credit Agreement obligates Q5000 Holdings to meet certain minimum financial requirements, including liquidity, consolidated debt service coverage and collateral maintenance.

The following discussion summarizes certain material U.S. federal income tax consequences, as of the date of this prospectus supplement, of the purchase, ownership, and disposition (including by conversion) of the notes and, where noted, the ownership and disposition of our common stock into which the notes may be converted. This discussion is based upon the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), its legislative history, Treasury regulations promulgated or proposed thereunder (“Treasury Regulations”), published rulings and judicial decisions, each as of the date of this prospectus supplement. Those authorities are subject to change, possibly with retroactive effect, or are subject to different interpretations. Changes in these authorities, subsequent to the date of this prospectus or retroactively applied, may cause the U.S. federal income tax consequences to vary substantially from the consequences described below. This discussion only applies to Holders (as defined below) that purchase the notes on original issue for cash at their “issue price” (the first price at which a substantial portion of the notes is sold for cash to persons other than bond houses, brokers, or similar persons or organizations acting in the capacity of underwriters, placement agents or wholesalers) and hold the notes or our common stock as “capital assets” within the meaning of Section 1221 of the Code (generally, property held for investment). For purposes of this discussion, “Holder” means either a U.S. Holder (as defined below) or a Non-U.S. Holder (as defined below) or both, as the context may require.

This discussion does not describe all of the U.S. federal income tax consequences that may be relevant to a Holder in light of its particular circumstances (including the Medicare tax imposed on certain investment income under Section 1411 of the Code and the alternative minimum tax) and does not address the U.S. federal income tax consequences to Holders that may be subject to special treatment under U.S. federal income tax laws, including (without limitation):

If an entity or arrangement classified as a partnership for U.S. federal income tax purposes holds the notes or our common stock, the tax treatment of a partner of such partnership will generally depend upon the status of the partner, certain determinations made at the partner level and the activities of the partnership. If you are a partner of an entity or arrangement that is classified as a partnership for U.S. federal income tax purposes and is holding the notes or our common stock, you should consult your own tax advisor.

This discussion does not address tax consequences arising under the laws of any foreign, state or local jurisdiction or any U.S. federal taxes (such as the federal estate tax or the federal gift tax) other than U.S. federal income taxes. We have not sought, and do not intend to seek, any private letter rulings from the U.S. Internal Revenue Service (the “IRS”) with respect to any of the tax consequences discussed below. As such, no assurance can be given that the IRS or a court will agree with the treatment of the notes or our common stock described herein.

This discussion is provided for general information only and does not constitute legal advice to any potential purchaser of the notes. If you are considering the purchase of the notes, you should consult your own tax advisor concerning the U.S. federal income tax consequences of purchasing, owning, and disposing (including by converting) of the notes and the owning and disposing of our common stock into which the notes may be convertible in light of your particular circumstances, any other U.S. federal tax consequences (including any gift or estate tax consequences), and any consequences arising under any tax treaty or the laws of any state, local or foreign taxing jurisdiction.

In certain circumstances, we may elect or be obligated to pay additional amounts on the notes in excess of stated interest and stated principal on the notes (see “Description of Notes — Optional Redemption” and “Description of Notes — Events of Default”). These potential payments may implicate the provisions of the Treasury Regulations applicable to “contingent payment debt instruments.” We do not intend to treat the possibility of paying such additional amounts as causing the notes to be treated as contingent payment debt instruments; however, additional income may be recognized if any such additional payment is made. It is possible that the IRS may take a different position, in which case, if such position is sustained, it could significantly alter the timing, amount and character of a Holder’s income, gain or loss with respect to the notes from that which is described below. You should consult your own tax advisor regarding the possible application of the contingent payment debt instrument rules to the notes.

The remainder of this discussion assumes that the notes will be indebtedness for U.S. federal income tax purposes that is not subject to the contingent payment debt instrument regulations.

The following discussion applies only to U.S. Holders. For purposes of this discussion, a “U.S. Holder” is a beneficial owner of a note or our common stock received upon conversion of a note that is for U.S. federal income tax purposes:

Any stated interest on a note generally will be taxable to a U.S. Holder as ordinary income at the time the interest is received or accrued in accordance with such U.S. Holder’s regular method of accounting for U.S. federal income tax purposes.

Except as provided below under “— Conversion of the Notes,” upon the sale, exchange, redemption, or other taxable disposition of a note, a U.S. Holder will generally recognize gain or loss equal to the difference between the amount realized on such sale, exchange, redemption, or other taxable disposition (excluding any amount attributable to accrued but unpaid interest, which will be taxable as ordinary interest income to the extent the U.S. Holder has not previously included the accrued interest in income) and such U.S. Holder’s adjusted tax basis in the note. A U.S. Holder’s amount realized will equal the amount of cash plus the fair market value of any other property received for the note. A U.S. Holder’s adjusted tax basis in its note will generally be equal to the price paid for the note plus any amount previously included in income as a result of an adjustment (or failure to make an adjustment) to the conversion rate of the note as described below under “— Deemed Distributions.” Any such gain or loss will be long-term capital gain or loss if the note was held for more than one year at the time of the sale, exchange, redemption, or other taxable disposition. Long-term capital gains of individuals, estates and trusts currently are generally eligible for reduced rates of U.S. federal income tax. The deductibility of capital losses may be subject to limitation.

The conversion rate of the notes will be adjusted in certain circumstances. See “Description of Notes — Adjustments to the Conversion Rate,” “Description of Notes — Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” and “Description of Notes — Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change” above. Adjustments (or failure to make adjustments) that are considered to have the effect of increasing the proportionate interest of a U.S. Holder of a note in our assets or earnings and profits may result in a deemed distribution to the U.S. Holder for U.S. federal income tax purposes, even though the U.S. Holder has not received any cash or property as a result of such adjustments. Adjustments to the conversion rate made pursuant to a bona fide reasonable adjustment formula that have the effect of preventing the dilution of the interest of the Holders of the notes, however, will generally not be considered to result in a deemed distribution. Certain of the possible conversion rate adjustments provided in the notes (including, without limitation, adjustments in respect of taxable dividends to holders of our common stock and, under certain circumstances, adjustments to the conversion rate upon a make-whole fundamental change) will not qualify as being pursuant to a bona fide reasonable adjustment formula. If such an adjustment is made and does not so qualify, a U.S. Holder generally will be deemed to have received a distribution even if the U.S. Holder does not receive any cash or property as a result of such adjustment. Any deemed distributions will be taxed in the same manner as an actual distribution (see “— Distributions on Common Stock” below), but may not be eligible for the reduced rates of tax applicable to the receipt of certain dividend income by non-corporate U.S. Holders or the dividends-received deduction. Generally, a U.S. Holder’s adjusted tax basis in a note will be increased to the extent any such deemed distribution is treated as a dividend. Because a deemed dividend would not give rise to any cash from which any applicable withholding tax could be satisfied, if backup withholding is required with respect to a U.S. Holder’s notes (because of the U.S. Holder’s failure to establish an exemption from backup withholding taxes as further described below in “— Backup Withholding and Information Reporting”), such withholding may be made from subsequent payments of cash or common stock on the notes (or, in some circumstances, any payments on our common stock) or from sales proceeds paid or credited to, or other funds or assets of, such U.S. Holder.

We are currently required to report the amount of any deemed distributions on our website or to the IRS and to Holders of notes not exempt from information reporting. The IRS proposed regulations addressing the amount and timing of deemed distributions, as well as obligations of withholding agents and filing and notice obligations of issuers in respect of such deemed distributions. If adopted as proposed, the regulations would generally provide that (i) the amount of a deemed distribution is the excess of the fair market value of the right to acquire stock immediately after the conversion rate adjustment over the fair market value of the right to acquire stock (immediately after the conversion rate adjustment) without the adjustment, (ii) the deemed distribution occurs at the earlier of the date the adjustment occurs under the terms of the note and the date of the actual distribution of cash or property that results in the deemed distribution, (iii) subject to certain limited exceptions, a withholding agent is required to impose any applicable withholding on deemed distributions and, if there is no associated cash payment, may set off its withholding obligations against payments on the notes (or, in some circumstances, any payments on our common stock) or sales proceeds received by or other funds or assets of an investor and (iv) we are required to report the amount of any deemed distributions on our

website or to the IRS and to all Holders of notes (including Holders of notes that would otherwise be exempt from information reporting). The final regulations will be effective for deemed distributions occurring on or after the date of adoption, but Holders of notes and withholding agents may rely on them prior to that date under certain circumstances.

U.S. Holders should consult their tax advisors regarding the proper treatment to them of adjustments (or failure to make adjustments) to the conversion rate and deemed distributions.

Upon conversion of the notes, we may deliver solely shares of our common stock (and cash in lieu of fractional shares), solely cash, or a combination of shares of our common stock and cash at our election, as described above under “Description of Notes — Settlement Elections.”

Generally, a U.S. Holder will not recognize gain or loss on the conversion of the notes solely into shares of common stock except to the extent of (1) cash received in lieu of fractional shares (which will be treated as described below in “— Fractional Shares”) and (2) common stock attributable to accrued but unpaid interest, which will be taxable as ordinary interest income to the extent a U.S. Holder has not previously included the accrued interest in income. The initial tax basis in the shares of common stock received (including any fractional share deemed received) by a U.S. Holder upon conversion of the notes (other than common stock received by a U.S. Holder that is attributable to accrued but unpaid interest, the tax basis of which would equal its fair market value) will be equal to the U.S. Holder’s aggregate adjusted tax basis in the notes converted. The holding period for the shares of common stock received by a U.S. Holder upon conversion of the notes generally will include the period during which the U.S. Holder held the notes prior to the conversion, except that the holding period of any common stock received with respect to accrued but unpaid interest will commence on the day after the date of receipt.

If we deliver solely cash upon such a conversion, a U.S. Holder’s gain or loss will be determined in the same manner as if the Holder disposed of the notes in a taxable sale (as described above under “— Sale, Exchange, Redemption or Other Taxable Disposition of the Notes”).

If, upon a conversion, we pay a combination of cash (other than cash solely for fractional shares) and common stock to a U.S. Holder in exchange for the notes, the U.S. federal income tax consequences of such a conversion are unclear. U.S. Holders should consult their tax advisors regarding the consequences of such a conversion. It is possible that the conversion may be treated as a recapitalization or as a taxable exchange in part as discussed below.

If, upon a conversion, we pay a combination of cash (other than cash solely for fractional shares) and common stock to a U.S. Holder in exchange for the notes, we intend to take the position that the notes are securities for U.S. federal income tax purposes and that, as a result, the exchange would be treated as a recapitalization of the notes in exchange for our common stock. Under such circumstances, a U.S. Holder would generally recognize capital gain, but not loss, equal to the lesser of (1) the excess of the sum of the fair market value of the common stock received (including any fractional share deemed received) and the amount of cash received (other than amounts attributable to accrued but unpaid interest, which will be taxable as ordinary interest income to the extent the Holder has not previously included the accrued interest in income, and cash in lieu of fractional shares) over the U.S. Holder’s adjusted tax basis in the notes, and (2) the amount of cash received by the U.S. Holder (excluding amounts attributable to accrued but unpaid interest and cash in lieu of fractional shares). In such case, a U.S. Holder’s holding period for the shares of common stock received upon such conversion would include the period during which the note was held (except that the holding period for shares of our common stock received with respect to accrued but unpaid interest would begin on the day after the date of receipt), and a U.S. Holder’s adjusted tax basis in the shares of our common stock received (including any

fractional shares deemed received) upon such conversion (other than common stock received that is attributable to accrued but unpaid interest, the tax basis of which would equal its fair market value) would equal such U.S. Holder’s adjusted tax basis in the notes at the time of such conversion, decreased by the amount of cash received (other than any cash received in lieu of a fractional share of our common stock or attributable to accrued but unpaid interest), and increased by the amount of gain recognized, if any (other than any gain recognized with respect to the deemed redemption of a fractional share of our common stock).

Alternatively, if the conversion of notes into cash (other than cash solely for fractional shares) and common stock were not treated as a recapitalization:

In such case, the U.S. Holder’s adjusted tax basis in the notes would generally be allocated pro rata among our common stock received (including any fractional shares deemed received that are treated as sold for cash) and the portion of the notes that is treated as sold for cash (other than, in each case, any common stock, fractional shares or cash received with respect to accrued but unpaid interest), based on their fair market values. The holding period for our common stock received in the conversion would include the U.S. Holder’s holding period for the note, except that the holding period of any common stock received with respect to accrued but unpaid interest would commence on the day after our common stock is received.

Any capital gain or loss recognized under the foregoing rules generally will be long-term capital gain or loss if the U.S. Holder’s holding period in the notes is more than one year at the time of disposition. Long-term capital gains of individuals, estates and trusts currently are generally subject to reduced rates of taxation. The deductibility of capital losses is subject to limitations.

A U.S. Holder that receives cash in lieu of a fractional share of our common stock upon conversion will be treated as if the fractional share was issued and received and then immediately redeemed for cash. This deemed redemption of the fractional share generally will result in recognition of capital gain or loss equal to the difference between the amount of cash received in such deemed redemption and the U.S. Holder’s adjusted tax basis in the fractional share exchanged.

Any such capital gain or loss recognized generally will be long-term capital gain or loss if the U.S. Holder’s holding period for the notes is more than one year at the time of conversion. Long-term capital gains of individuals, estates and trusts currently are generally eligible for reduced rates of U.S. federal income tax. The deductibility of capital losses may be subject to limitation.

In certain circumstances, a U.S. Holder whose notes are surrendered for conversion during the period from the close of business on any regular record date to the open of business on the next interest payment date must make a payment equal to the amount of interest payable on the notes so converted. See “Description of Notes — Interest Payments” above. U.S. Holders should consult their own tax advisors concerning the appropriate treatment of such payment, including the amount of such payment that is allocable to accrued interest.

In certain situations, the notes may become convertible into shares of an acquirer or other property other than our common stock. See “Description of Notes — Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” above. Depending on the circumstances, (1) such an

adjustment could result in a deemed exchange of the notes by a U.S. Holder and the modified notes could be treated as newly issued at that time, possibly resulting in the recognition of taxable gain or loss for U.S. federal income tax purposes, and (2) such modified notes could be subject to different U.S. federal income tax treatment than the original notes (including, for example, that an exchange of the modified notes into shares of an acquirer or other property other than our common stock could be a taxable event for U.S. federal income tax purposes regardless of the chosen settlement method). U.S. Holders are urged to consult their own tax advisors regarding the U.S. federal income tax consequences of such an adjustment or exchange and a deemed issuance of modified notes.

Distributions, if any, made to a U.S. Holder with respect to our common stock held by the U.S. Holder (other than certain distributions of common stock) will generally result in dividend income to the extent of our current or accumulated earnings and profits as determined for U.S. federal income tax purposes. The amount of any such distribution in excess of our current and accumulated earnings and profits will first be applied to reduce the U.S. Holder’s tax basis in such common stock, and any amount in excess of such U.S. Holder’s tax basis will be treated as gain from the sale or exchange of such common stock, the tax treatment of which is discussed below under “— Sale, Exchange or Other Taxable Dispositions of Common Stock.” Any such dividend may be eligible for the dividends-received deduction if the U.S. Holder is an otherwise qualifying corporate Holder that meets the holding period and other requirements for the dividends-received deduction. Dividends received by non-corporate U.S. Holders may be subject to U.S. federal income tax at lower rates than other types of ordinary income if certain conditions are met. U.S. Holders should consult their own tax advisors regarding their qualification for the dividends-received deduction and the lower rates on dividends.

Upon a sale, exchange or other taxable disposition of our common stock, a U.S. Holder generally will recognize capital gain or loss in an amount equal to the difference between the amount realized and such U.S. Holder’s adjusted tax basis in the common stock, and such gain or loss will be long-term capital gain or loss if the U.S. Holder’s holding period in the common stock is more than one year at the time of the disposition. Long-term capital gains of individuals, estates and trusts currently are generally subject to reduced rates of taxation. The deductibility of capital losses may be subject to limitations.

Information reporting generally will apply to the payment (or deemed payment) of interest and deemed dividends with respect to the notes held by a U.S. Holder and dividends on our common stock held by a U.S. Holder, and the proceeds of the sale or other disposition (including a redemption, exchange or retirement) of notes and our common stock held by a U.S. Holder, unless, in each case, the U.S. Holder is a recipient that is exempt from such information reporting (such as a corporation) and, if requested, the U.S. Holder certifies as to that status. Backup withholding generally will apply to such payments (or deemed payments) unless the U.S. Holder provides its taxpayer identification number to the withholding agent, certified under penalties of perjury, as well as certain other information, or otherwise establishes an exemption from backup withholding. Backup withholding is not an additional tax. The amount of any backup withholding will generally be allowed as a credit against the U.S. Holder’s U.S. federal income tax liability and may entitle the U.S. Holder to a refund, provided that the U.S. Holder timely furnishes the required information to the IRS.

The following discussion applies only to Non-U.S. Holders. For purposes of this discussion, the term “Non-U.S. Holder” means a beneficial owner of a note or our common stock received upon conversion of a note that is an individual, corporation, estate or trust for U.S. federal income tax purposes and, in each case, is not a U.S. Holder.

Subject to the discussion below under “— Backup Withholding and Information Reporting” and “Material U.S. Federal Income Tax Considerations — Foreign Account Tax Compliance Act,” any payment to a Non-U.S. Holder of interest on the notes will be exempt from U.S. federal income and withholding tax if the Non-U.S. Holder properly certifies as to its foreign status, as described below, and:

The exemption from taxation and withholding described above generally applies only if the Non-U.S. Holder (1) appropriately certifies that it is not a United States person (which certification may be made on a properly completed and executed IRS Form W-8BEN or W-8BEN-E (or other applicable form)) to the applicable withholding agent or (2) holds its notes through certain foreign intermediaries and satisfies the certification requirements of applicable Treasury Regulations. Special rules apply to foreign partnerships, estates and trusts, and in certain circumstances certifications as to the foreign status of partners, trust owners or beneficiaries may have to be provided to the applicable withholding agent.

If a Non-U.S. Holder cannot satisfy the requirements described above, payments of interest on the notes will be subject to the 30% U.S. federal withholding tax unless the Non-U.S. Holder provides the applicable withholding agent with a properly completed and executed (i) IRS Form W-8BEN or W-8BEN-E (or other applicable form) claiming an exemption from or reduction in withholding tax under the benefit of an applicable tax treaty or (ii) IRS Form W-8ECI (or other applicable form) providing that interest paid on the notes is not subject to withholding tax because it is effectively connected with its conduct of a trade or business in the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment or fixed base within the United States), in which case such interest will be taxable as discussed below under “— Income or Gain Effectively Connected with a U.S. Trade or Business.”

Any distributions made to a Non-U.S. Holder with respect to our common stock (and any deemed distributions resulting from certain adjustments, or failure to make adjustments, to the conversion rate of the notes, as described under “— Material U.S. Federal Income Tax Consequences to U.S. Holders — Deemed Distributions” above) that are treated as dividends for U.S. federal income tax purposes (see “— Material U.S. Federal Income Tax Consequences to U.S. Holders — Distributions on Common Stock” above for a discussion on when distributions will be treated as dividends for U.S. federal income tax purposes) will be subject to U.S. federal withholding tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty as to which the Non-U.S. Holder appropriately claims the benefit. Because a deemed dividend would not give rise to any cash from which any applicable withholding tax could be satisfied, if withholding taxes (including any applicable backup withholding) are paid on behalf of a Non-U.S. Holder, those withholding taxes may be withheld from payments of interest and payments of cash or common stock upon conversion, repurchase or maturity of the notes or sales proceeds received by a Non-U.S. Holder, or if any withholding taxes (including backup withholding) are paid on behalf of a Non-U.S. Holder, those amounts may be set off against such payments of cash or common stock (or, in some circumstances, any payments on our common stock) or sales proceeds received by, or other funds or assets of, such Non-U.S. Holder. Dividends that are effectively connected

with a trade or business conducted by a Non-U.S. Holder within the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment or fixed base within the United States) are not subject to the U.S. federal withholding tax described above if the Non-U.S. Holder meets the certification requirements described below and are taxable as discussed below under “— Income or Gain Effectively Connected with a U.S. Trade or Business.”

A Non-U.S. Holder of shares of common stock who wishes to claim the benefit of an applicable treaty rate is required to satisfy applicable certification requirements (generally by providing a properly completed and executed IRS Form W-8BEN or W-8BEN-E (or other applicable form) claiming such benefit). A Non-U.S. Holder of shares of common stock who wishes to claim an exemption from withholding for dividends effectively connected with a trade or business is required to satisfy applicable certification requirements (generally by providing a properly completed and executed IRS Form W-8ECI (or other applicable form) claiming such benefit). If a Non-U.S. Holder is eligible for an exemption or a reduced rate of U.S. federal withholding tax pursuant to an income tax treaty, such Non-U.S. Holder may generally obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Subject to the discussion below under “— Backup Withholding and Information Reporting” and “Material U.S. Federal Income Tax Considerations — Foreign Account Tax Compliance Act,” any gain realized by a Non-U.S. Holder upon the sale, exchange, or other taxable disposition of notes or shares of our common stock received upon a conversion of the notes as well as upon the conversion of a note into cash or into a combination of cash and stock (excluding, in each case, amounts attributable to accrued but unpaid interest, which generally will be treated as interest and may be subject to the rules discussed above in “— Interest on the Notes”) generally will not be subject to U.S. federal income tax or withholding tax unless:

We believe that we are not, have never been and will not become a USRPHC. If we are or become a USRPHC, a Non-U.S. Holder generally will not be subject to U.S. federal income tax or withholding tax upon the sale, exchange, retirement, redemption, repurchase or other disposition of the notes or our common stock solely as a result of our status as a USRPHC as long as our common stock is and continues to be regularly traded on an established securities market unless the Non-U.S. Holder meets certain ownership thresholds with respect to the notes or our common stock. Generally, a corporation is a USRPHC only if the fair market value of its U.S. real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests plus certain other assets used or held for use in a trade or business. Non-U.S. Holders should consult their tax advisors regarding the application of the USRPHC rules.

A Non-U.S. Holder described in the first bullet point above will be subject to tax as described in “— Income or Gain Effectively Connected with a U.S. Trade or Business” below. An individual Non-U.S. Holder described in the second bullet point above will be subject to a flat tax at a rate of 30% (or a lower applicable treaty rate) on the gain recognized on the conversion of the notes or from the sale, exchange or other taxable disposition of the notes or our common stock, which may be offset by certain U.S. source capital losses, even though such individual is not considered a resident of the United States. For purposes of the immediately preceding sentence, such gains and losses shall be taken into account only if, and to the extent that, they would be recognized and taken into account if such gains and losses were effectively connected with the conduct of a trade or business within the United States (see “— Income or Gain Effectively Connected with a U.S. Trade or Business” below), subject to certain adjustments.

Upon the conversion of the notes into a combination of shares of our common stock and cash, a Non-U.S. Holder may realize gain or loss under the circumstances described above under “— Material U.S. Federal Income Tax Consequences to U.S. Holders — Conversion of the Notes.” The U.S. federal income tax consequences to a Non-U.S. Holder of realizing any gain would be as described above under “— Sale, Exchange or Other Taxable Disposition of Notes or of Shares of Common Stock.”

Upon the conversion of the notes solely into cash, the U.S. federal income tax consequences to a Non-U.S. Holder would be generally as described above under “— Sale, Exchange or Other Taxable Disposition of Notes or of Shares of Common Stock.”

In certain circumstances, a Non-U.S. Holder whose notes are surrendered for conversion during the period from the close of business on any regular record date to the open of business on the next interest payment date must make a payment equal to the amount of interest payable on the notes so converted. See “Description of Notes — Interest Payments” above. Non-U.S. Holders should consult their own tax advisors concerning the appropriate treatment of such payment, including the amount of such payment that is allocable to accrued interest.

In certain situations, the notes may become convertible into shares of an acquirer or other property other than our common stock. See “Description of Notes — Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” above. Depending on the circumstances, (1) such an adjustment could result in a deemed exchange of the notes by a Non-U.S. Holder subject to the rules described above under “— Sale, Exchange or Other Taxable Disposition of Notes or of Shares of Common Stock” and the modified notes could be treated as newly issued at that time, and (2) such modified notes could be subject to different U.S. federal income tax treatment than the original notes. Non-U.S. Holders are urged to consult their own tax advisors regarding the U.S. federal income tax consequences of such an adjustment or exchange and a deemed issuance of modified notes.

If any interest on the notes, dividends (including deemed dividends) on our common stock or with respect to the notes or gain from the sale, redemption, conversion, exchange or other taxable disposition of the notes or our common stock is effectively connected with a trade or business conducted by a Non-U.S. Holder within the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment or fixed base within the United States), then the interest, dividends or gain generally will be subject to U.S. federal income tax at regular graduated income tax rates in generally the same manner as if the Non-U.S. Holder were a U.S. Holder. If a Non-U.S. Holder is a corporation, that portion of its earnings and profits that is effectively connected with its trade or business within the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment or fixed base within the United States) also may be subject to a “branch profits tax” (at a rate of 30% or such lower rate as may be specified by an applicable income tax treaty). Even though, absent treaty relief, effectively connected interest or dividends are subject to U.S. federal income tax, and may be subject to the branch profits tax, they are generally not subject to withholding tax if the Non-U.S. Holder provides to the applicable withholding agent a properly completed and executed IRS Form W-8ECI (or appropriate substitute or successor form) or IRS Form W-8BEN or W-8BEN-E (or appropriate successor form) claiming exemption under an applicable income tax treaty, as applicable, subject to the discussion below under “Material U.S. Federal Income Tax Considerations — Foreign Account Tax Compliance Act.”

Section 871(m) of the Code and related Treasury Regulations require withholding at a 30% rate (or lower rate provided under an applicable treaty) on dividend equivalents paid or deemed paid to Non-U.S. Holders with respect to certain financial transactions (including debt instruments) linked to U.S. equities. To the extent these Treasury Regulations are applicable, withholding may be required even in the absence of any actual dividend related payment made pursuant to the terms of the instrument. For example, an adjustment to the conversion rate to account for a dividend payment could result in a dividend equivalent.

Under IRS administrative guidance, the Treasury Department and IRS have indicated that they intend to revise applicable Treasury Regulations to provide that Section 871(m) will generally not apply to any payment made with respect to any “non-delta-one” transaction issued before January 1, 2023 (subject to certain exceptions).

The IRS administrative guidance states that taxpayers may rely on such guidance until amended Treasury Regulations are promulgated. For this purpose, “delta” generally means the ratio of the change in the fair market value of an equity linked instrument to a small change in the fair market value of the number of shares of the underlying security referenced by the equity linked instrument.

Based on our expectation that, as of their issue date, the notes will have a delta of less than one, we do not expect the notes to be subject to withholding under the Section 871(m) rules. However, it is possible that the notes could be treated as deemed reissued for U.S. federal income tax purposes upon the occurrence of certain events, and following such occurrence the notes could be treated as subject to withholding on dividend equivalent payments. In certain limited circumstances, it is possible for Non-U.S. Holders to be liable for tax under these rules with respect to a combination of transactions treated as having been entered into in connection with each other even when no withholding is required. Non-U.S. holders should consult their own tax advisors concerning these Treasury Regulations, subsequent official guidance and any other possible alternative characterizations of the notes for U.S. federal income tax purposes.

Generally, the amount of interest and deemed distributions with respect to the notes and distributions on our common stock paid (or deemed paid) to a Non-U.S. Holder and the amount of tax, if any, withheld with respect to those payments must be reported to the IRS and to the Non-U.S. Holder. Copies of these information returns may also be made available to the tax authorities in a country in which the Non-U.S. Holder resides under the provisions of an applicable income tax treaty. A Non-U.S. Holder may be subject to backup withholding and certain information reporting with respect to payments (or deemed payments) of interest or deemed distributions with respect to the notes and distributions on our common stock, and (under certain circumstances) the proceeds of a sale or other disposition of the notes or our common stock, unless the Non-U.S. Holder certifies to its foreign status or otherwise establishes an exemption (and the applicable withholding agent does not have actual knowledge or reason to know that the Non-U.S. Holder is a United States person). Backup withholding is not an additional tax. The amount of any backup withholding will generally be allowed as a credit against the Non-U.S. Holder’s U.S. federal income tax liability and may entitle the Non-U.S. Holder to a refund, provided that the Non-U.S. Holder timely furnishes the required information to the IRS.

Sections 1471 through 1474 of the Code and the Treasury Regulations and administrative guidance issued thereunder (referred to as “FATCA”) generally impose withholding at a rate of 30% on interest and dividends (including deemed dividends) on the notes or our common stock paid (or deemed paid) to a “foreign financial institution” or a “non-financial foreign entity” (each as defined in the Code) (including, in some cases, when such foreign financial institution or non-financial foreign entity is acting as an intermediary), unless: (1) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments, and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners); (2) in the case of a non-financial foreign entity, such entity certifies that it does not have any “substantial United States owners” (as defined in the Code) or provides the withholding agent with a certification identifying its direct and indirect substantial United States owners; or (3) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. Intergovernmental agreements regarding FATCA between the United States and certain other countries may modify the foregoing requirements. Under certain circumstances, a beneficial owner of notes or our common stock might be eligible for refunds or credits of such taxes.

Holders are urged to consult with their own tax advisors regarding the possible implications of FATCA on the notes and our common stock.

THE PRECEDING DISCUSSION OF MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS IS FOR GENERAL INFORMATION ONLY AND IS NOT TAX ADVICE. ANY POTENTIAL PURCHASER OF THE NOTES IS URGED TO CONSULT ITS OWN TAX ADVISOR REGARDING THE PARTICULAR U.S. FEDERAL (INCLUDING FEDERAL ESTATE TAX AND FEDERAL GIFT TAX), STATE, LOCAL AND FOREIGN TAX CONSEQUENCES OF PURCHASING, HOLDING, CONVERTING AND DISPOSING OF THE NOTES AND HOLDING AND DISPOSING OF COMMON STOCK RECEIVED UPON CONVERSION, INCLUDING THE CONSEQUENCES OF ANY PROPOSED CHANGES IN APPLICABLE LAWS.

Subject to the terms and conditions set forth in an underwriting agreement by and among Wells Fargo Securities, LLC and Evercore Group L.L.C., as representatives for the underwriters named in the agreement, and us, we have agreed to sell to each underwriter, and each underwriter has agreed, severally and not jointly, to purchase from us, the principal amount of notes set forth opposite its name in the table below:

Under the terms of the underwriting agreement, the underwriters are committed to purchase this entire amount of notes if any notes are purchased. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the non-defaulting underwriters may be increased or the underwriting agreement may be terminated.

We have agreed to indemnify the underwriters and their controlling persons against certain liabilities in connection with this offering, including liabilities under the Securities Act, or to contribute to payments the underwriters may be required to make because of any of those liabilities.

The underwriting agreement provides that the underwriters’ obligation to purchase the notes depends on the satisfaction of the conditions contained in the underwriting agreement. The conditions contained in the underwriting agreement include the requirement that the representations and warranties made by us to the underwriters are true and that we deliver to the underwriters customary closing documents.

The underwriters propose initially to offer the notes directly to the public at the public offering price set forth on the cover of this prospectus supplement, plus accrued interest from the original issue date of the notes, if any, and to certain dealers at such price less a concession not in excess of 1.5% of the principal amount of the notes, plus accrued interest from the original issue date of the notes, if any. If all of the notes are not sold at the public offering price, the representatives of the underwriters may change the public offering price and the other selling terms.

The following table shows the per note and total underwriting discount that we will pay to the underwriters.

We estimate that the total expenses related to this offering payable by us and not reimbursed, excluding the underwriting discount, will be approximately $1.0 million. We have also agreed to reimburse the underwriters for certain of their expenses incurred in connection with the offering in an amount up to $10,000.

The notes are a new issue of securities with no established trading market. We do not intend to apply for a listing of the notes on any stock exchange. We have been advised by the underwriters that they intend to make a market in the notes but they are not obligated to do so and may discontinue market making at any time without notice. Accordingly, we cannot assure you that a liquid trading market will develop for the notes, that you will be able to sell your notes at a particular time or that prices that you receive when you sell will be favorable. If an active public trading market for the notes does not develop or is not maintained, the market price and liquidity of the notes may be adversely affected.

We have agreed with the underwriters that, without the prior written consent of Wells Fargo Securities, LLC and Evercore Group L.L.C., we will not, and our executive officers and our directors have agreed with the underwriters that, without the prior written consent of Wells Fargo Securities, LLC, they will not, for a period of 60 days after the date of this prospectus supplement, subject to certain exceptions, (i) directly or indirectly, issue, offer, sell, agree to issue, offer or sell, solicit offers to purchase, grant any call option, warrant or other right to purchase, purchase any put option or other right to sell, pledge, borrow or otherwise dispose of any shares of our common stock or any securities convertible into or exchangeable for shares of our common stock, (ii) establish or increase any “put equivalent position” or liquidate or decrease any “call equivalent position”, in each case within the meaning of Section 16 of the Exchange Act, with respect to any shares of our common stock or any securities convertible into or exchangeable for shares of our common stock, or (iii) otherwise enter into any swap, derivative or other transaction or arrangement that transfers to another, in whole or in part, any economic consequence of ownership of our common stock or any securities convertible into or exercisable or exchangeable for our common stock, whether or not such transaction is to be settled by delivery of securities, cash or other consideration, each without the prior written consent of Wells Fargo Securities, LLC and, solely with respect to us, Evercore Group L.L.C. However, Wells Fargo Securities, LLC and Evercore Group L.L.C. may, in their sole discretion and at any time without notice, release all or any portion of the securities subject to these lock-up agreements. When determining whether to release securities from the lock-up agreements, Wells Fargo Securities, LLC and Evercore Group L.L.C. may consider, among other factors, market conditions at the time, the number of securities for which the release is requested and the shareholder’s reasons for requesting the release.

Notwithstanding the above, we will not be prohibited from issuing shares of our common stock upon conversion of the notes offered hereby or from (A) the conversion or exchange of convertible or exchangeable securities outstanding on the date hereof; (B) the exercise of currently outstanding options or the vesting of restricted stock or restricted stock units outstanding on the date hereof; (C) the exercise of currently outstanding warrants; (D) the entry into arrangements relating to transactions described in this prospectus supplement under the heading “Description of the Concurrent Capped Call Transactions”; (E) the entry into, or consummation of, repurchases of the Existing Notes; and (F) grants of employee or director options or restricted stock under, or the issuance and sale of shares pursuant to, employee or director equity-based plans in effect on the date hereof, each as described in this prospectus supplement or the documents incorporated by reference herein.

Until the distribution of the notes is completed, SEC rules may limit the underwriters from bidding for and purchasing the notes or our common stock. However, the underwriters may engage in transactions that stabilize the price of the notes or our common stock, such as bids or purchases of notes or shares of our common stock in the open market while this offering is in progress to peg, fix or maintain that price. These transactions also may include short sales and purchases to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater principal amount of notes than they are required to purchase in this offering. “Covered” short sales are made in an amount not greater than the underwriters’ over-allotment option. The underwriters may reduce that short position by purchasing notes in the open market or by exercising all or part of the over-allotment option described above. In determining the source of notes to close out the covered short position, the underwriters will consider, among other things, the price of notes available for purchase in the open market as compared to the price at which they may purchase additional notes pursuant to the option granted to them. “Naked” short sales are any sales in excess of such option. The underwriters must close out any naked short position by purchasing notes in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the notes in the open market after pricing that could adversely affect investors who purchase in this offering.

The underwriters may also impose a penalty bid. This occurs when a particular underwriter repays to the underwriters a portion of the underwriting discount received by it because the representatives have repurchased notes sold by or for the account of such underwriter in stabilizing or short covering transactions.

Neither we nor the underwriters make any representation or prediction as to the effect the transactions described above may have on the price of the notes or our common stock. Any of these activities may have the

effect of preventing or retarding a decline in the market price of the notes. They may also cause the price of the notes to be higher than the price that would otherwise exist on the open market in the absence of these transactions. If the underwriters commence any of these transactions, they may discontinue them without notice at any time.

In connection with the offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means, such as e-mail.

The underwriters and/or their respective affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The underwriters and/or their respective affiliates have from time to time provided, and expect to provide in the future, investment banking, commercial banking and other financial services to us and our affiliates, for which they have received, and may continue to receive, customary fees and commissions. In the ordinary course of their various business activities, the underwriters and/or their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investment and securities activities may involve securities and/or instruments of ours. The underwriters and/or their respective affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments. In addition, affiliates of Wells Fargo Securities, LLC and HSBC Securities (USA) Inc. are party to the capped call transactions described below and elsewhere in this prospectus supplement.

In connection with the pricing of the notes, we entered into capped call transactions with the option counterparties. The capped call transactions cover, subject to customary adjustments, the number of shares of common stock initially underlying the notes. The capped call transactions are expected generally to reduce the potential dilution to our common stock upon conversion of the notes or at our election (subject to certain conditions) offset any cash payments we are required to make in excess of the aggregate principal amount of converted notes, as the case may be, with such reduction or offset subject to a cap. We intend to use approximately $10.5 million of the net proceeds from this offering to pay the cost of the capped call transactions.

In connection with establishing their initial hedges of the capped call transactions, we have been advised that the option counterparties or their respective affiliates expect to enter into various cash-settled over-the-counter derivative transactions with respect to our common stock concurrently with or shortly after the pricing of the notes and may unwind these cash-settled over-the-counter derivative transactions and purchase shares of our common stock in open market transactions following the pricing of the notes. This activity could increase (or reduce the size of any decrease in) the market price of our common stock or the notes at that time.

In addition, we have been advised that the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding various derivatives with respect to our common stock and/or purchasing or selling our common stock or other securities of ours in secondary market transactions following the pricing of the notes and from time to time prior to the maturity of the notes (and are likely to do so on each exercise date of the capped call transactions, which are expected to occur during the 40 trading day period beginning on the 41st scheduled trading day prior to the maturity date of the notes, or following any termination of any portion of the capped call transactions in connection with any repurchase, exchange, redemption or conversion of the notes if we make the relevant election under the capped call transactions). This activity could also cause or avoid an increase or a decrease in the market price of our common stock or the notes, which could affect your ability to convert the notes and, to the extent the activity occurs during any observation period related to a conversion of notes, it could affect the number of shares and value of the consideration that you will receive upon conversion of the notes.

For a discussion of the potential impact of any market or other activity by the option counterparties or their respective affiliates in connection with these capped call transactions, see “Risk Factors—Risks Related to the Notes and the Underlying Shares of Common Stock—The capped call transactions may affect the value of the notes and our common stock.”

The notes may be sold in Canada only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the notes must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including the accompanying prospects and any amendment hereto or thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 (or, in the case of securities issued or guaranteed by the government of a non-Canadian jurisdiction, section 3A.4) of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

The notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area (“EEA”) or in the United Kingdom (“UK”). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client as defined in point (11) of Article 4(1) of Directive 2014/65/EU (as amended, “MiFID II”); or (ii) a customer within the meaning of Directive (EU) 2016/97 (as amended, the “Insurance Distribution Directive”), where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II; or (iii) not a qualified investor as defined in Regulation (EU) 2017/1129 (as amended, the “Prospectus Regulation”). Consequently no key information document required by Regulation (EU) No 1286/2014 (as amended, the “PRIIPs Regulation”) for offering or selling the notes or otherwise making them available to retail investors in the EEA or in the UK has been prepared and therefore offering or selling the notes or otherwise making them available to any retail investor in the EEA or in the UK may be unlawful under the PRIIPS Regulation. This prospectus supplement has been prepared on the basis that any offer of the notes in any Member State of the EEA will be made pursuant to an exemption under the Prospectus Regulation from the requirement to publish a prospectus for offers of the notes. This prospectus supplement is not a prospectus for the purposes of the Prospectus Regulation.

References to Regulations or Directives include, in relation to the UK, those Regulations or Directives as they form part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 or have been implemented in UK domestic law, as appropriate.

The above selling restriction is in addition to any other selling restrictions set out below.

This document is for distribution only to persons who (i) have professional experience in matters relating to investments and who qualify as investment professionals within the meaning of Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (as amended, the “Financial Promotion Order”), (ii) are persons falling within Article 49(2)(a) to (d) (“high net worth companies, unincorporated associations etc.”) of the Financial Promotion Order, (iii) are outside the United Kingdom, or (iv) are persons to whom an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the Financial Services and Markets Act 2000, as amended (“FSMA”)) in connection with the issue or sale of any securities may otherwise lawfully be communicated or caused to be communicated (all such persons together being referred to as “relevant persons”). This document is directed only at relevant persons and must not be acted on or relied on by persons who are not relevant persons. Any investment or investment activity to which this document relates is available only to relevant persons and will be engaged in only with relevant persons.

The notes may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange (“SIX”) or on any other stock exchange or regulated trading facility in Switzerland. This document has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the notes or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, the Company, the notes have been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of the notes will not be supervised by, the Swiss Financial Market Supervisory Authority FINMA (FINMA), and the offer of the notes has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes (“CISA”). The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of the notes.

In the Netherlands, the notes may only be offered to qualified investors (gekwalificeerde beleggers) within the meaning of section 1:1 of the Dutch Financial Supervision Act (Wet op het financieel toezicht). This prospectus supplement has not been approved by, registered or filed with the Netherlands Authority for the Financial Markets.

This prospectus supplement relates to an Exempt Offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority (“DFSA”). This prospectus supplement is intended for distribution only to persons of a type specified in the Offered Securities Rules of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement nor taken steps to verify the information set forth herein and has no responsibility for the prospectus supplement. The notes to which this prospectus supplement relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the notes offered should conduct their own due diligence on the notes. If you do not understand the contents of this prospectus supplement you should consult an authorized financial advisor.

No placement document, prospectus, product disclosure statement or other disclosure document has been lodged with the Australian Securities and Investments Commission (“ASIC”), in relation to the offering. This prospectus does not constitute a prospectus, product disclosure statement or other disclosure document under the Corporations Act 2001 (the “Corporations Act”), and does not purport to include the information required for a prospectus, product disclosure statement or other disclosure document under the Corporations Act.

Any offer in Australia of the notes may only be made to persons (the “Exempt Investors”) who are “sophisticated investors” (within the meaning of section 708(8) of the Corporations Act), “professional investors” (within the meaning of section 708(11) of the Corporations Act) or otherwise pursuant to one or more exemptions contained in section 708 of the Corporations Act so that it is lawful to offer the notes without disclosure to investors under Chapter 6D of the Corporations Act.

The notes applied for by Exempt Investors in Australia must not be offered for sale in Australia in the period of 12 months after the date of allotment under the offering, except in circumstances where disclosure to investors under Chapter 6D of the Corporations Act would not be required pursuant to an exemption under section 708 of the Corporations Act or otherwise or where the offer is pursuant to a disclosure document which complies with Chapter 6D of the Corporations Act.

Further, any shares of our common stock issued on conversion of the notes must not be offered for sale in Australia in the period of 12 months after the date of issue of those shares of common stock except in circumstances where disclosure to investors under Chapter 6D of the Corporations Act would not be required

pursuant to an exemption under section 708 of the Corporations Act or otherwise or where the offer is pursuant to a disclosure document which complies with Chapter 6D of the Corporations Act. Any person acquiring notes or common stock must observe such Australian on-sale restrictions.

This prospectus supplement contains general information only and does not take account of the investment objectives, financial situation or particular needs of any particular person. It does not contain any securities recommendations or financial product advice. Before making an investment decision, investors need to consider whether the information in this prospectus supplement is appropriate to their needs, objectives and circumstances, and, if necessary, seek expert advice on those matters.

The notes have not been offered or sold and will not be offered or sold in Hong Kong, by means of any document, other than (a) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong and any rules made under that Ordinance; or (b) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies Ordinance (Cap. 32) of Hong Kong or which do not constitute an offer to the public within the meaning of that Ordinance. No advertisement, invitation or document relating to the notes has been or may be issued or has been or may be in the possession of any person for the purposes of issue, whether in Hong Kong or elsewhere, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to the notes which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the Securities and Futures Ordinance and any rules made under that Ordinance.

The notes have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (Law No. 25 of 1948, as amended) and, accordingly, will not be offered or sold, directly or indirectly, in Japan, or for the benefit of any Japanese Person or to others for re-offering or resale, directly or indirectly, in Japan or to any Japanese Person, except in compliance with all applicable laws, regulations and ministerial guidelines promulgated by relevant Japanese governmental or regulatory authorities in effect at the relevant time. For the purposes of this paragraph, “Japanese Person” shall mean any person resident in Japan, including any corporation or other entity organized under the laws of Japan.

This prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, the notes were not offered or sold or caused to be made the subject of an invitation for subscription or purchase and will not be offered or sold or caused to be made the subject of an invitation for subscription or purchase, and this prospectus supplement or any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the notes, has not been circulated or distributed, nor will it be circulated or distributed, whether directly or indirectly, to any person in Singapore other than (i) to an institutional investor (as defined in Section 4A of the Securities and Futures Act (Chapter 289) of Singapore, as modified or amended from time to time (the “SFA”)) pursuant to Section 274 of the SFA, (ii) to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA, or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the notes are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

securities or securities-based derivatives contracts (each term as defined in Section 2(1) of the SFA) of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the notes pursuant to an offer made under Section 275 of the SFA except:

Our counsel, Baker Botts L.L.P., Houston, Texas, will pass upon certain legal matters for us in connection with the offering of the notes. Goodwin Procter LLP will pass upon certain legal matters for us in connection with the capped call transactions. Maslon LLP, Minneapolis, Minnesota, will pass upon matters governed by Minnesota law. Certain legal matters will be passed upon for the underwriters by Latham & Watkins LLP.

The consolidated financial statements of Helix Energy Solutions Group, Inc. and subsidiaries as of December 31, 2019 and 2018, and for each of the years in the three-year period ended December 31, 2019, and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2019, have been incorporated by reference herein and in the registration statement in reliance upon the reports of KPMG LLP, an independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report covering the December 31, 2019 financial statements refers to a change in the method of accounting for leases as of January 1, 2019.

 

Corporate Secretary
Helix Energy Solutions Group, Inc.
3505 West Sam Houston Parkway North, Suite 400
Houston, Texas 77043
(281) 618-0400