As filed with the Securities and Exchange Commission on March 2, 2018

Registration No. 333-222662

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1 to

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

MCDERMOTT INTERNATIONAL, INC.

COMET I B.V.

(Exact name of registrant as specified in its charter)

John M. Freeman

Senior Vice President,

General Counsel & Corporate Secretary

McDermott International, Inc.

4424 West Sam Houston Parkway North

Houston, Texas 77041

(281) 870-5000

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of the proposed sale of the securities to the public: As soon as practicable after this registration statement becomes effective and upon completion of the combination described in the enclosed document.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box.  ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act:

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer)  ☐

Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)  ☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act or until this registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to Section 8(a), may determine.

EXPLANATORY NOTE

This registration statement contains:

in each case, pursuant to the Business Combination Agreement, dated as of December 18, 2017, as amended January 24, 2018, by and among McDermott, McDermott Bidco, CB&I, CB&I Newco and the other parties thereto.

The joint proxy statement/prospectus and the exchange offer prospectus will be identical in all substantive respects, except that certain sections of the joint proxy statement/prospectus will be eliminated or replaced with alternative pages, or additional pages will be included, in the exchange offer prospectus, as set forth in the table below:

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Information contained herein is subject to completion or amendment. A registration statement relating to these securities has been filed with the Securities and Exchange Commission. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This joint proxy statement/prospectus shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful.

SUBJECT TO COMPLETION, DATED MARCH 2, 2018

JOINT PROXY STATEMENT/PROSPECTUS

McDermott International, Inc., a Panamanian corporation referred to as “McDermott,” and Chicago Bridge & Iron Company N.V., a public company with limited liability incorporated under the laws of the Netherlands referred to as “CB&I,” have entered into a Business Combination Agreement, dated as of December 18, 2017 (as it may be amended or supplemented from time to time, the “Business Combination Agreement”). Pursuant to the terms of the Business Combination Agreement, McDermott and CB&I have agreed to combine their businesses by a series of transactions (and subject to the terms and conditions of the Business Combination Agreement) that we refer to as the “Core Transactions,” preceded by McDermott Technology, B.V., a company organized under the laws of the Netherlands and a direct wholly owned subsidiary of McDermott referred to as “McDermott Bidco,” making an Exchange Offer (as defined herein) (together with the Core Transactions, the “Combination”) for shares of CB&I Common Stock (as defined herein). Subject to the terms and conditions of the Business Combination Agreement, the Combination shall occur as follows:

As a result of the Core Transactions, shareholders of CB&I who do not validly tender in (or who properly withdraw their shares of CB&I Common Stock from) the Exchange Offer and, as a result of the Merger, become CB&I Newco shareholders, will be entitled to receive, in respect of each former share of CB&I Common Stock, upon completion of the Liquidation, 2.47221 shares of McDermott Common Stock, or, if the McDermott Reverse Stock Split (as defined below) has occurred prior to the date on which the Exchange Offer Effective Time occurs, 0.82407 shares of McDermott Common Stock (as applicable, the “Exchange Offer Ratio”), together with cash in lieu of fractional shares, subject to applicable withholding taxes, including the Dutch Dividend Withholding Tax. The consideration per share of CB&I Common Stock to be received pursuant to the Core Transactions is the same as the Exchange Offer Ratio, except that the receipt of shares of McDermott Common Stock and cash in lieu of fractional shares of McDermott Common Stock pursuant to the Liquidation generally will be subject to the Dutch Dividend Withholding Tax. McDermott Common Stock is listed on the New York Stock Exchange (“NYSE”) under the trading symbol “MDR,” and CB&I Common Stock is listed on the NYSE under the trading symbol “CBI.” We encourage you to obtain quotes for the McDermott Common Stock and CB&I Common Stock.

The Core Transactions will be subject to and (other than the CB&I Technology Acquisition, which will occur no later than immediately prior to the Exchange Offer Effective Time) occur promptly after the Exchange Offer Effective Time (and in any event on the Closing Date, other than the Liquidation Distribution, which shall occur on the Closing Date or as soon as practicable thereafter). We refer to the Core Transactions and the Exchange Offer together as the “Combination.”

Based on the estimated number of shares of CB&I Common Stock and McDermott Common Stock that will be outstanding immediately prior to the closing of the Combination, we estimate that, upon closing of the Combination, McDermott stockholders will own approximately 53% of the outstanding shares of McDermott Common Stock and CB&I shareholders will own approximately 47% of the outstanding shares of McDermott Common Stock, assuming all CB&I shareholders participate in the Exchange Offer (such that their share ownership would not be reduced as a result of withholding for the Dutch Dividend Withholding Tax).

Pursuant to the Business Combination Agreement, the approval of CB&I shareholders and McDermott stockholders must be obtained before effecting the Combination and the other transactions contemplated by the Business Combination Agreement.

CB&I and McDermott will each hold a special general meeting or special meeting of its respective shareholders or stockholders in connection with the proposed Combination.

At the CB&I Special General Meeting (as defined herein), CB&I shareholders will be asked to vote on: (1) a proposal to amend the articles of association of CB&I as set forth in Annex G attached hereto to remove the supermajority voting requirement for certain resolutions when any person, alone or together with a group, holds more than fifteen percent (15%) of the outstanding share capital of CB&I (the “Articles Amendment Resolution”); (2) a proposal to enter into and effectuate the Merger in accordance with the Merger Proposal (as defined herein) (the “Merger Resolution”); (3) a proposal to approve the CB&I Technology Acquisition (to the extent required by applicable law) and the Share Sale (the “Sale Resolutions”); (4) a proposal to, effective as of the Share Sale Effective Time (as defined herein), (a) approve the dissolution of CB&I Newco, (b) approve the appointment of a liquidator of CB&I Newco and (c) approve the appointment of a custodian of the books and records of CB&I Newco in accordance with Section 2:24 of the Dutch Civil Code (the “Liquidation Resolutions”); (5) a proposal to, effective as of the Exchange Offer Effective Time, provide full and final discharge to each member of the CB&I boards for their acts of management or supervision, as applicable, up to the date of the CB&I Special General Meeting, other than for acts as a result of fraud (bedrog), gross negligence (grove schuld) or willful misconduct (opzet) (the “Discharge Resolutions”); and (6) a proposal to approve, by non-binding, advisory vote, the compensation payable to CB&I’s named executive officers in connection with the Combination. The CB&I Special General Meeting may be canceled and reconvened, if necessary and in accordance with the terms of the Business Combination Agreement, to re-solicit proxies if there are not sufficient votes to approve the Articles Amendment Resolution, the Merger Resolution, the Sale Resolutions, the

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Liquidation Resolutions or the Discharge Resolutions. The CB&I Management Board and Supervisory Board recommend that the CB&I shareholders vote “FOR” each of the proposals to be considered at the CB&I Special General Meeting.

At the McDermott Special Meeting (as defined herein), McDermott stockholders will be asked to vote on: (1) a proposal to amend McDermott’s amended and restated articles of incorporation, as amended to date (the “McDermott Articles”), to (a) effect a 3-to-1 reverse stock split (the “McDermott Reverse Stock Split”) of the McDermott Common Stock and (b) decrease the authorized shares of McDermott Common Stock to 255,000,000 shares, an amount sufficient to enable the transactions contemplated under the Business Combination Agreement following the McDermott Reverse Stock Split (the “McDermott Reverse Stock Split Articles Amendment Resolution”); (2) if the McDermott Reverse Stock Split Articles Amendment Resolution is not approved, a proposal to amend the McDermott Articles to increase the authorized shares of McDermott Common Stock to 765,000,000 shares of McDermott Common Stock, an amount sufficient to enable the transactions contemplated under the Business Combination Agreement without the McDermott Reverse Stock Split (the “McDermott Authorized Capital Articles Amendment Resolution”); (3) a proposal to issue shares of McDermott Common Stock in connection with the Exchange Offer and the Core Transactions, including the issuance pursuant to the Exchangeable Note (the “McDermott Stock Issuance”); and (4) a proposal to approve the adjournment of the McDermott Special Meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the McDermott Stock Issuance and either the McDermott Reverse Stock Split Articles Amendment Resolution or the McDermott Authorized Capital Articles Amendment Resolution. The McDermott Board of Directors recommends that the McDermott stockholders vote “FOR” each of the proposals to be considered at the McDermott Special Meeting.

The Combination cannot be completed unless the CB&I shareholders approve the Merger Resolution, the Sale Resolution, the Liquidation Resolution and the Discharge Resolutions and the McDermott stockholders approve the McDermott Stock Issuance and either the McDermott Reverse Stock Split Articles Amendment Resolution or the McDermott Authorized Capital Articles Amendment Resolution.

Because the Exchange Offer Ratio is fixed, the value of the shares of McDermott Common Stock that CB&I shareholders will receive upon completion of the Combination will depend on the price per share of McDermott Common Stock at the time the Combination is completed. That price will not be known at the time of the CB&I Special General Meeting or McDermott Special Meeting and may be greater or less than the current price of the McDermott Common Stock or the price of shares of McDermott Common Stock at the time of the CB&I Special General Meeting or the McDermott Special Meeting.

Your vote is very important, regardless of the number of shares you own. Whether or not you expect to attend the special general meeting or special meeting in person, as applicable, please submit a proxy to vote your shares as promptly as possible so that your shares may be represented and voted at such meeting.

The obligations of CB&I and McDermott to complete the Combination are subject to the satisfaction or waiver of several conditions set forth in the Business Combination Agreement. More information about CB&I, McDermott, the CB&I Special General Meeting, the McDermott Special Meeting and the Combination, including the Exchange Offer, the Merger, the Share Sale and the Liquidation, is contained in this joint proxy statement/prospectus. Before voting, we urge you to read carefully and in their entirety the accompanying joint proxy statement/prospectus, including the Annexes and the documents incorporated by reference. In particular, we urge you to read carefully the section entitled “Risk Factors” beginning on page 25 of this joint proxy statement/prospectus.

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We look forward to the successful combination of McDermott and CB&I.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under this joint proxy statement/prospectus or determined that this joint proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

This joint proxy statement/prospectus is dated [—], 2018 and is first being mailed to stockholders of McDermott and shareholders of CB&I on or about [—], 2018.

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REFERENCES TO ADDITIONAL INFORMATION

This document incorporates important business and financial information about McDermott, McDermott Bidco, CB&I and CB&I Newco from other documents that are not included in or delivered with this document. This information is available to you without charge upon your request. You can obtain copies of the documents incorporated by reference into this document through the U.S. Securities and Exchange Commission website at www.sec.gov or by requesting them in writing or by telephone from the appropriate company at the following addresses and telephone numbers:

In addition, you may also obtain additional copies of this document or the documents incorporated by reference into this document by contacting MacKenzie Partners, Inc., McDermott’s proxy solicitor, or Innisfree M&A Incorporated, CB&I’s proxy solicitor, at the addresses and telephone numbers listed below. You will not be charged for any of these documents that you request.

Investors may also consult the websites of McDermott or CB&I for more information concerning the combination and the other transactions described in this document. The website of McDermott is www.mcdermott.com and the website of CB&I is www.cbi.com. Information included on these websites is not incorporated by reference into this document.

If you would like to request any documents, please do so by [—], 2018, in order to receive them before the special meeting and the special general meeting.

See “Where You Can Find More Information” for more detail.

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4424 West Sam Houston Parkway North

Houston, Texas 77041

(281) 870-5000

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS OF MCDERMOTT INTERNATIONAL, INC. TO BE HELD ON [—], 2018

To the Stockholders of McDermott International, Inc.:

You are cordially invited to a special meeting of stockholders of McDermott International, Inc., a Panamanian corporation (“McDermott”), which will be held at [—], on [—], 2018, at [—] [a./p.]m. local time (the “McDermott Special Meeting”), for the following purposes:

The McDermott Board of Directors has fixed the close of business on [—], 2018 as the record date for determination of McDermott stockholders entitled to receive notice of, and to vote at, the McDermott Special Meeting or any adjournment thereof. Only holders of record of issued and outstanding shares of McDermott Common Stock at the close of business on the record date are entitled to receive notice of, and to vote at, the McDermott Special Meeting or any adjournment thereof.

The affirmative vote of the holders of a majority of the shares of McDermott Common Stock outstanding and entitled to vote at the McDermott Special Meeting (meaning that, of the shares of McDermott Common Stock outstanding, excluding treasury shares, a majority must be voted “FOR” the proposal) is required to approve the McDermott Reverse Stock Split Articles Amendment Resolution and the McDermott Authorized Capital Articles Amendment Resolution. Failures to vote, abstentions and broker non-votes will have the same effect as votes “AGAINST” the adoption of the McDermott Reverse Stock Split Articles Amendment Resolution and the adoption of the McDermott Authorized Capital Articles Amendment Resolution. The affirmative vote of the holders of a majority of the votes cast on the matter by holders of shares of McDermott Common Stock present in person or represented by proxy at the McDermott Special Meeting (meaning the number of shares voted “FOR” the proposal must exceed the number of shares voted “AGAINST” the proposal plus abstentions) is required to approve the McDermott Stock Issuance proposal. Because failures to vote and broker non-votes are not actual votes cast (assuming that a quorum is present), they will have no effect on the outcome of the vote on the McDermott Stock Issuance proposal. However, under applicable rules of the NYSE, an abstention will have the same effect as a vote “AGAINST” the McDermott Stock Issuance proposal. The affirmative vote of the holders of a majority of the shares of McDermott Common Stock present in person or represented by proxy at the meeting, whether or not a quorum is present, is required to approve the McDermott Meeting Adjournment proposal. Failures to vote by McDermott stockholders that attend the McDermott Special Meeting in person, abstentions and broker non-votes will have the same effect as votes “AGAINST” the McDermott Meeting Adjournment proposal. Failures to vote by McDermott stockholders not attending the McDermott Special Meeting, in person or by proxy, will have no effect on the McDermott Meeting Adjournment proposal, whether or not a quorum is present.

The Combination (as defined in the Business Combination Agreement) cannot be completed unless the McDermott stockholders approve the McDermott Stock Issuance and either the McDermott Reverse Stock Split Amendment Resolution or the McDermott Authorized Capital Articles Amendment Resolution.

If you are a stockholder of record, you can vote your shares in person at the McDermott Special Meeting or vote now by giving your proxy via Internet, telephone or mail. You may give your proxy by following the instructions included in the enclosed proxy card. If you vote using either the telephone or the Internet, you will save McDermott mailing expenses.

By giving your proxy, you will be directing the persons named as proxies in the accompanying proxy card for the McDermott Special Meeting how to vote your shares at the meeting. Even if you plan on attending the McDermott Special Meeting, we urge you to vote now by giving us your proxy. This will ensure that your vote is represented at the meeting. If you do attend the McDermott Special Meeting, you can change your vote at that time, if you then desire to do so.

If you are the beneficial owner of shares, but not the holder of record, you should refer to the instructions provided by your broker or nominee for further information. The broker or nominee that holds your shares has the authority to vote them, absent your approval, only as to matters for which they have discretionary authority under the applicable NYSE rules. None of the proposals for the McDermott Special Meeting are considered routine matters. This means that brokers or nominees may not vote your shares with respect to those matters if they have not been given specific instructions as to how to vote. Please be sure to give specific voting instructions to your broker or nominee.

You should have received a voting instruction form from your broker or nominee that holds your shares. For shares of which you are the beneficial owner but not the holder of record, follow the instructions contained in the voting instruction form to vote by Internet, telephone or mail. If you want to vote your shares in person at the McDermott Special Meeting, you must obtain a valid proxy from your broker or nominee. You should contact your broker or nominee or refer to the instructions provided by your broker or nominee for further information. Additionally, the availability of telephone or Internet voting depends on the voting process used by the broker or nominee that holds your shares.

The enclosed proxy statement/prospectus provides a detailed description of the Combination, the Business Combination Agreement and the other matters to be considered at the McDermott Special Meeting. We urge you to read this joint proxy statement/prospectus, including any documents incorporated by reference, and the Annexes carefully and in their entirety. If you have any questions regarding the accompanying joint proxy statement/prospectus, you may contact MacKenzie Partners, Inc., McDermott’s proxy solicitor, by calling toll-free at (800) 322-2885.

BY ORDER OF THE BOARD OF DIRECTORS

/s/ David Dickson

David Dickson

President and Chief Executive Officer

McDermott International, Inc.

[—], 2018

YOUR VOTE IS VERY IMPORTANT. PLEASE VOTE YOUR SHARES PROMPTLY, WHETHER OR NOT YOU EXPECT TO ATTEND THE MCDERMOTT SPECIAL MEETING. YOU CAN FIND INSTRUCTIONS FOR VOTING ON THE ENCLOSED PROXY CARD. IF YOU ARE UNCERTAIN OF HOW YOU HOLD YOUR SHARES OR NEED ASSISTANCE IN VOTING YOUR SHARES, PLEASE CONTACT MACKENZIE PARTNERS, INC., MCDERMOTT’S PROXY SOLICITOR.

105 Madison Avenue

New York, New York 10016

(212) 929-5500 (Call Collect)

or

Call Toll-Free (800) 322-2885

Email: proxy@mackenziepartners.com

Chicago Bridge & Iron Company N.V.

Prinses Beatrixlaan 35

2595 AK The Hague

The Netherlands

011 31 70 373 2010

CHICAGO BRIDGE & IRON COMPANY N.V.

NOTICE AND AGENDA OF SPECIAL GENERAL MEETING OF SHAREHOLDERS

TO BE HELD ON [—], 2018

To the Shareholders of Chicago Bridge & Iron Company N.V.:

You are cordially invited to a special meeting of shareholders of Chicago Bridge & Iron Company N.V., a public company with limited liability incorporated under the laws of the Netherlands (“CB&I”), which will be held at [—], on [—], 2018, at [—] [a./p.]m. local time (the “CB&I Special General Meeting”), for the following purposes and with the following agenda:

The CB&I Management Board has fixed the close of business on [—], 2018 as the record date for determination of CB&I shareholders entitled to attend, and to vote at, the CB&I Special General Meeting. Only holders of record of issued and outstanding shares of CB&I common stock, par value EUR 0.01 per share (“CB&I Common Stock”), registered in the CB&I share register as referred to in section 2:85 of the Dutch Civil Code, part of which is kept by Computershare Trust Company, N.A. on behalf of CB&I (the “CB&I Share Register”) at the close of business on the record date are entitled to attend and to vote at, the CB&I Special General Meeting, even if such shareholders have already tendered their shares of CB&I Common Stock in the Exchange Offer (as defined in the Business Combination Agreement). Unless the context otherwise requires, references to “shareholders” refer to those who on the record date are, and are registered in the CB&I Share Register as, holders of shares of CB&I Common Stock or others with meeting rights under Dutch law with respect to shares of CB&I Common Stock.

The affirmative vote of a majority of the votes cast on the matter by holders of shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting (meaning the number of shares voted “FOR” the proposal must exceed the number of shares voted “AGAINST” the proposal) is required to approve the Articles Amendment Resolution, the Sale Resolutions, the Liquidation Resolutions, the Discharge Resolutions and the Compensation Resolution at the CB&I Special General Meeting.

Assuming the Articles Amendment Resolution is adopted and implemented and so long as at least fifty percent (50%) of the issued and outstanding CB&I share capital is present at the CB&I Special General Meeting, in person or by proxy, the affirmative vote of a majority of the votes cast on the matter by holders of shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting (meaning the number of shares voted “FOR” the proposal must exceed the number of shares voted “AGAINST” the proposal) is required to approve the Merger Resolution. If less than fifty percent (50%) of the issued and outstanding CB&I share capital is present at the CB&I Special General Meeting, in person or by proxy, the affirmative vote of at least two-thirds of the votes cast on the matter by holders of shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting is required to approve the Merger Resolution. Failures to vote by CB&I shareholders that attend the CB&I Special General Meeting in person or by proxy, failures to vote by CB&I shareholders that do not attend the CB&I Special General Meeting in person or by proxy, abstentions and broker non-votes are not considered votes cast and therefore will have no effect on the outcome of the proposals.

However, if the Articles Amendment Resolution is not adopted at the CB&I Special General Meeting and there is a person that alone or together with a group (beneficially) holds more than fifteen percent (15%) of the issued and outstanding share capital of CB&I, the affirmative vote of at least eighty percent (80%) of the shares of CB&I Common Stock outstanding is required to approve the Merger Resolution. In such case, failures to vote by CB&I shareholders, whether or not they attend the CB&I Special General Meeting in person or by proxy, abstentions and broker non-votes will have the same effect as votes “AGAINST” the adoption of the Merger Resolution.

The Combination (as defined in the Business Combination Agreement) cannot be completed unless the CB&I shareholders approve the Merger Resolution, the Sale Resolutions (to the extent required by applicable law), the Liquidation Resolutions and the Discharge Resolutions.

If you are a shareholder of record registered in the CB&I Share Register, you may vote your shares in person by attending the CB&I Special General Meeting, or vote now by giving your proxy via Internet or mail. You may give your proxy by following the instructions included in the enclosed proxy card. If you give your proxy to vote using the Internet, you will save CB&I mailing expenses.

Admittance of shareholders and acceptance of written voting proxies shall be governed by Dutch law. Only shareholders registered in the CB&I Share Register as of the record date, or such shareholders’ proxies, who have requested that the holder of the CB&I Share Register (either the CB&I Management Board or Computershare Trust Company N.A.) notify CB&I by [—], 2018 of his or her or his or her proxy’s intention to attend the CB&I Special General Meeting, and other persons with a statutory right to attend or otherwise admitted by the chairman of the meeting may attend the CB&I Special General Meeting. The notice must state the name and number of shares the person will represent at the CB&I Special General Meeting. All attendees must be prepared to identify themselves with a valid proof of identity for admittance.

If you are the beneficial owner of shares, but not the holder of record, you should refer to the instructions provided by your broker or nominee for further information. The broker or nominee that holds your shares has the authority to vote them, absent your approval, only as to matters for which they have discretionary authority under the applicable NYSE rules. None of the proposals for the CB&I Special General Meeting are considered routine matters. This means that brokers or nominees may not vote your shares with respect to those matters if they have not been given specific instructions as to how to vote. Please be sure to give specific voting instructions to your broker or nominee.

You should have received a voting instruction form from your broker or nominee that holds your shares. For shares of which you are the beneficial owner but not the holder of record, follow the instructions contained in the voting instruction form to vote by Internet, telephone or mail. The availability of telephone or Internet voting depends on the voting process used by the broker or nominee that holds your shares. By giving your proxy, you will be directing the persons named as proxies in the accompanying proxy card for the CB&I Special General Meeting how to vote your shares at the meeting. If you wish to attend the CB&I Special General Meeting, you must request a proxy from your broker or nominee. Even if you plan on attending the CB&I Special General Meeting, we urge you to vote now by giving us your proxy. This will ensure that your vote is represented at the meeting. If you do attend the CB&I Special General Meeting, you can change your vote at that time, if you then desire to do so.

The enclosed proxy statement/prospectus provides a detailed description of the Combination, the Business Combination Agreement and the other matters to be considered at the CB&I Special General Meeting. We urge you to read this joint proxy statement/prospectus, including any documents incorporated by reference, and the Annexes carefully and in their entirety. If you have any questions regarding the accompanying joint proxy statement/prospectus, you may contact Innisfree M&A Incorporated, CB&I’s proxy solicitor, by calling toll-free at (877) 825-8971.

BY ORDER OF THE MANAGEMENT BOARD

/s/ Patrick Mullen

Patrick Mullen

President and Chief Executive Officer

Chicago Bridge & Iron Company N.V.

[—], 2018

YOUR VOTE IS VERY IMPORTANT. PLEASE VOTE YOUR SHARES PROMPTLY, WHETHER OR NOT YOU EXPECT TO ATTEND THE CB&I SPECIAL MEETING. YOU CAN FIND INSTRUCTIONS FOR VOTING ON THE ENCLOSED PROXY CARD. IF YOU ARE UNCERTAIN OF HOW YOU HOLD YOUR SHARES OR NEED ASSISTANCE IN VOTING YOUR SHARES, PLEASE CONTACT INNISFREE M&A INCORPORATED, CB&I’S PROXY SOLICITOR, AT (212) 750-5833 (BANKS AND BROKERAGE FIRMS) AND (877) 825-8971 (STOCKHOLDERS TOLL FREE).

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS

Except where specifically noted, the following information and all other information contained in this document does not give effect to the proposed reverse stock split described in McDermott Proposal No. 1.

The following are answers to some questions that you, as a stockholder of McDermott International, Inc., a Panamanian corporation (which we refer to as “McDermott”), or as a shareholder of Chicago Bridge & Iron Company N.V., a public company with limited liability incorporated under the laws of the Netherlands (which we refer to as “CB&I”), may have regarding the proposed transactions between McDermott and CB&I. You are urged to read this entire document carefully, including its annexes and the other documents referenced herein in their entirety, because this section may not provide all of the information that is important to you with respect to the Combination (as defined herein), the Business Combination Agreement (as defined herein), McDermott, CB&I and the other parties to the Business Combination Agreement. Additional important information is contained in the annexes to, and the documents incorporated by reference into, this document. You may obtain the information incorporated by reference into this document without charge by following the instructions under the section entitled “Where You Can Find More Information” beginning on page 215 of this document. Unless the context otherwise requires, references to “shareholders” refer to those who on the record date are, and are registered in the CB&I Share Register (as defined below) as holders of shares of CB&I Common Stock or others with meeting rights under Dutch law with respect to shares of CB&I Common Stock.

About the Combination

This document is a prospectus that will be used in connection with the offer by McDermott Technology, B.V., a company organized under the laws of the Netherlands (“McDermott Bidco”), to exchange each share of common stock, par value EUR 0.01, of CB&I (“CB&I Common Stock”) for a specified number of shares of common stock, par value $1.00 per share, of McDermott (“McDermott Common Stock”) and is a joint proxy statement/prospectus that:

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This document contains important information about the Combination and the transactions comprising it, the Business Combination Agreement, and the McDermott Special Meeting and the CB&I Special General Meeting, and you should read it carefully. The enclosed voting materials allow you to vote your shares without attending a special meeting.

As a result of the Core Transactions, shareholders of CB&I who do not validly tender in (or who properly withdraw their shares of CB&I Common Stock from) the Exchange Offer and, as a result of the Merger, become CB&I Newco shareholders, will be entitled to receive, in respect of each former share of CB&I Common Stock, upon completion of the Liquidation, 2.47221 shares of common stock, par value $1.00 of McDermott (“McDermott Common Stock”), or, if the McDermott Reverse Stock Split (as defined below) has occurred prior to the date on which the Exchange Offer Effective Time (as defined below) occurs, 0.82407 shares of McDermott Common Stock, together with cash in lieu of fractional shares. The consideration per share of CB&I Common Stock to be received pursuant to the Core Transactions is the same as the Exchange Offer Ratio, except that the receipt of shares of McDermott Common Stock and cash

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in lieu of fractional shares pursuant to the Liquidation generally will be subject to Dutch Dividend Withholding Tax.

If the Business Combination Agreement is terminated under specified circumstances, McDermott or CB&I may be required to pay the other party a termination fee of $60 million as described under “The Business Combination Agreement—Termination, Amendment and Waiver” beginning on page 148 of this document.

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Based on the closing price of the McDermott Common Stock on the NYSE on December 18, 2017, the last trading day before the public announcement of the Business Combination Agreement, the Per Share Consideration was $18.76 per share of CB&I Common Stock. Based on the closing price of the McDermott Common Stock on the NYSE on March 1, 2018, the most recent practicable trading day prior to the date of this document, the Per Share Consideration was $17.90 per share of CB&I Common Stock. We urge you to obtain current market quotations of McDermott Common Stock and CB&I Common Stock.

McDermott stockholders are not entitled to appraisal or dissenters’ rights with respect to the McDermott Reverse Stock Split.

In addition, holders of CB&I Common Stock who receive shares of McDermott Common Stock and cash in lieu of fractional shares pursuant to the Liquidation (rather than the Exchange Offer) generally will be subject to Dutch Dividend Withholding Tax.

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At the Merger Effective Time, each outstanding award of performance shares relating to CB&I Common Stock (each, a “CB&I Performance Share Award”) will be canceled and converted into the right to receive cash, without interest and less applicable withholding taxes, in an amount equal to (1) the product of (a) the Exchange Offer Ratio, (b) the target number of shares of CB&I Common Stock subject to the CB&I Performance Share Award and (c) the closing price for a share of McDermott Common Stock on the business day immediately preceding the date of the closing of the Combination plus (2) an amount equal to any dividend equivalents associated with the CB&I Performance Share Award at that time.

At the Merger Effective Time: (1) each outstanding restricted stock unit award granted by CB&I (“CB&I Restricted Stock Unit Awards”) that is held by a non-employee member of the CB&I Supervisory Board (whether or not vested); (2) each vested CB&I Restricted Stock Unit Award held by a member of a specific group of executive officers of CB&I that has not been settled; (3) each CB&I Restricted Stock Unit Award that vests in accordance with its terms as result of the Combination; and (4) each vested share of CB&I Common Stock deferred pursuant to any CB&I equity compensation plan, will, in each case, be converted into a right to receive (a) a number of shares of McDermott Common Stock equal to the product of (i) the number of shares of CB&I Common Stock subject to the original CB&I award and (ii) the Exchange Offer Ratio, rounded to the nearest whole number of shares, plus (b) cash in an amount equal to any dividend equivalents associated with the CB&I Restricted Stock Unit Award at that time, subject to applicable withholding taxes.

At the Merger Effective Time, each other outstanding CB&I Restricted Stock Unit Award will be converted into a right to receive an award of restricted stock units that will be settled in McDermott Common Stock with substantially the same terms as the original CB&I award, including the vesting schedule and any conditions and restrictions on receipt. The number of shares of McDermott Common Stock subject to the converted restricted stock unit award will be determined by multiplying the number of shares of CB&I Common Stock subject to the original CB&I Restricted Stock Unit Award by the Exchange Offer Ratio, rounded to the nearest whole number of shares. The transactions contemplated by the Business Combination Agreement will not be considered a change in control for purposes of any award of CB&I Restricted Stock Units granted on or after December 18, 2017.

The CB&I Employee Stock Purchase Plan and Supervisory Board Stock Purchase Plan were suspended effective January 1, 2018, and such plans will be terminated effective as of, and contingent upon, the Merger Effective Time.

About the Special Meetings

About the McDermott Special Meeting

McDermott stockholders are also being asked to consider and vote on a proposal to adopt a resolution providing for an amendment to the McDermott Articles (the “McDermott Authorized Capital Articles

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Amendment”) to increase the authorized shares of McDermott Common Stock to 765,000,000 shares (the “McDermott Authorized Capital Articles Amendment Resolution”). If adopted, the McDermott Authorized Capital Articles Amendment Resolution will only become effective if the McDermott Reverse Stock Split Articles Amendment Resolution is not adopted at the McDermott Special Meeting.

McDermott stockholders are also being asked to consider and vote on a proposal to issue shares of McDermott Common Stock in connection with the Exchange Offer and the Core Transactions, including the issuance pursuant to the Exchangeable Note, under the terms of the Business Combination Agreement (the “McDermott Stock Issuance”).

Finally, McDermott stockholders are being asked to consider and vote on a proposal to approve any motion to adjourn the McDermott Special Meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the McDermott Stock Issuance proposal and either the McDermott Reverse Stock Split Articles Amendment Resolution or the McDermott Authorized Capital Articles Amendment Resolution (the “McDermott Meeting Adjournment”).

The Combination cannot be completed unless the McDermott stockholders approve the McDermott Stock Issuance and either the McDermott Reverse Stock Split Amendment Resolution or the McDermott Authorized Capital Articles Amendment Resolution.

The affirmative vote of the holders of a majority of the votes cast on the matter by holders of shares of McDermott Common Stock present in person or represented by proxy at the McDermott Special Meeting (meaning the number of shares voted “FOR” the proposal must exceed the number of shares voted “AGAINST” such proposal plus abstentions) is required to approve the McDermott Stock Issuance proposal.

The affirmative vote of the holders of a majority of the shares of McDermott Common Stock present in person or represented by proxy at the meeting, whether or not a quorum is present, is required to approve the McDermott Meeting Adjournment.

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Accordingly, the McDermott Board recommends that McDermott stockholders vote:

Stephen G. Hanks, the dissenting director, did not vote in favor of the transaction due in large part to his stated belief that the business operated by CB&I is inherently subject to the types of problems that CB&I has been experiencing recently in connection with its four significant contracts that have negatively impacted CB&I’s results of operations in recent periods. See “McDermott’s Reasons for the Combination; Recommendation of the McDermott Board—Views of Dissenting Director.”

If you choose to attend the McDermott Special Meeting in person, a government-issued picture identification will be required to enter the McDermott Special Meeting. If you are the representative of a corporate or institutional stockholder, you must present valid photo identification along with proof that you are the representative of such stockholder. If your shares are held by a bank, broker, trust company or other nominee, you will be required to present evidence of your ownership of shares, which you can obtain from your broker, bank, trust company or other nominee.

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If you sign and return your proxy card without indicating your voting instructions, your shares will be voted “FOR” the adoption of the McDermott Reverse Stock Split Articles Amendment Resolution, the adoption of the McDermott Authorized Capital Articles Amendment Resolution, the adoption of the McDermott Stock Issuance proposal and the adoption of the McDermott Meeting Adjournment proposal, if necessary to solicit additional proxies.

If you do not instruct your bank, broker, trust company or other nominee on how to vote your shares, your nominee may not vote your shares on: (1) the proposal to adopt the McDermott Reverse Stock Split Articles Amendment Resolution (which will have the same effect as a vote “AGAINST” adoption of the McDermott Reverse Stock Split Articles Amendment Resolution); (2) the proposal to adopt the McDermott Authorized Capital Articles Amendment Resolution (which will have the same effect as a vote “AGAINST” adoption of the McDermott Authorized Capital Articles Amendment Resolution); (3) the adoption of the McDermott Stock Issuance proposal (which, assuming the presence of a quorum, will have no effect on the adoption of the McDermott Stock Issuance proposal); or (4) the adoption of the McDermott Meeting Adjournment proposal (which will have the same effect as a vote “AGAINST” adoption of the McDermott Meeting Adjournment proposal).

If you are the beneficial owner, but not the holder of record, of shares, you should follow the instructions in the information provided by your broker or nominee to change your vote before the meeting. If you want to change your vote as to shares of which you are the beneficial owner by voting in person at the McDermott Special Meeting, you must obtain a valid “legal proxy” from the broker or nominee that holds those shares for you.

Written notices of revocation and other communications with respect to the revocation of proxies should be addressed as follows: McDermott International, Inc. Attention: Corporate Secretary, 4424 West Sam Houston Parkway North, Houston, Texas 77041.

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If you are a stockholder of record of shares of McDermott Common Stock and your proxy card is signed and returned without voting instructions, it will be voted according to the recommendations of the McDermott Board.

If you are the beneficial owner, but not the holder of record, of shares of McDermott Common Stock and fail to provide voting instructions, your broker or other holder of record may not vote on the adoption of the McDermott Reverse Stock Split Articles Amendment Resolution, the adoption of the McDermott Authorized Capital Articles Amendment Resolution, the McDermott Stock Issuance proposal or the McDermott Meeting Adjournment proposal, and no votes will be cast on your behalf with respect to those matters.

Failures to vote, abstentions and broker non-votes will have the same effect as votes “AGAINST” the adoption of the McDermott Reverse Stock Split Articles Amendment Resolution and the adoption of the McDermott Authorized Capital Articles Amendment Resolution. Because failures to vote and broker non-votes are not actual votes cast (assuming that a quorum is present), they will have no effect on the outcome of the vote on the McDermott Stock Issuance proposal. However, under applicable rules of the NYSE, an abstention will have the same effect as a vote “AGAINST” the McDermott Stock Issuance proposal. Failures to vote by McDermott stockholders that attend the McDermott Special Meeting in person, abstentions and broker non-votes will have the same effect as votes “AGAINST” the McDermott Meeting Adjournment proposal. Failures to vote by McDermott stockholders not attending the McDermott Special Meeting, in person or by proxy, will have no effect on the McDermott Meeting Adjournment proposal, whether or not a quorum is present.

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If your shares are held in the name of a bank, broker, trust company or other nominee, please instruct your nominee to vote your shares by following the instructions you receive from your nominee.

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About the CB&I Special General Meeting

The Combination cannot be completed unless the CB&I shareholders approve the Merger Resolution, the Sale Resolutions (to the extent required by applicable law), the Liquidation Resolutions, and the Discharge Resolutions.

Assuming the Articles Amendment Resolution is adopted and implemented and so long as at least fifty percent (50%) of the issued and outstanding CB&I share capital is present at the CB&I Special General Meeting, in person or by proxy, the affirmative vote of a majority of the votes cast on the matter by holders of shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting (meaning the number of shares voted “FOR” the proposal must exceed the number of shares voted “AGAINST” the proposal) is required to approve the Merger Resolution at the CB&I Special General Meeting.

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If less than fifty percent (50%) of the issued and outstanding CB&I share capital is present at the CB&I Special General Meeting, in person or by proxy, the affirmative vote of at least two-thirds of the votes cast on the matter by holders of shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting is required to approve the Merger Resolution.

However, if the Articles Amendment Resolution is not adopted at the CB&I Special General Meeting and there is a person that alone or together with a group (beneficially) holds more than fifteen percent (15%) of the issued and outstanding share capital of CB&I at the time of the CB&I Special General Meeting, the affirmative vote of at least eighty percent (80%) of the shares of CB&I Common Stock outstanding and entitled to vote at the CB&I Special General Meeting (meaning that, of the shares of CB&I Common Stock outstanding, excluding treasury shares, at least 80% must be voted “FOR” the proposal) is required to approve the Merger Resolution. In such case, failures to vote by CB&I shareholders, whether or not they attend the CB&I Special General Meeting in person or by proxy, abstentions and broker non-votes will have the same effect as votes “AGAINST” the adoption of the Merger Resolution.

The CB&I Boards recommend that CB&I shareholders vote:

In addition, the CB&I Boards recommend that CB&I shareholders accept the Exchange Offer.

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Unless the context otherwise requires, references to “shareholders” refer to those who on the record date are, and are registered in the CB&I Share Register as, holders of shares of CB&I Common Stock or others with meeting rights under Dutch law with respect to shares of CB&I Common Stock.

Admittance of shareholders and acceptance of written voting proxies shall be governed by Dutch law. Only shareholders registered in the CB&I Share Register as of the record date, or such shareholders’ proxies, who have requested that the holder of the CB&I Share Register (either the CB&I Management Board or Computershare Trust Company, N.A.) notify CB&I by [—], 2018 of his or her or his or her proxy’s intention to attend the CB&I Special General Meeting, may attend the CB&I Special General Meeting. The notice must state the name and number of shares the person will represent at the CB&I Special General Meeting. All attendees must be prepared to identify themselves with a valid proof of identity for admittance.

If you are not a shareholder of record registered in the CB&I Share Register, you may not attend the CB&I Special General Meeting without the invitation of the chairman of the CB&I Supervisory Board. You may vote now by giving your proxy via Internet, telephone or mail. You may give your proxy by following the instructions included in the enclosed proxy card. If you vote using either the telephone or the Internet, you will save CB&I mailing expenses.

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If you sign and return your proxy card without indicating your voting instructions, your shares will be voted “FOR” each of the Articles Amendment Resolution, the Merger Resolution, the Sale Resolutions, the Liquidation Resolutions, the Discharge Resolutions and the Compensation Resolution.

If you do not instruct your bank, broker, trust company or other nominee on how to vote your shares, your nominee may not vote your shares on any of the proposals put forth for resolution at the CB&I Special General Meeting.

If you are the beneficial owner, but not the holder of record, of shares, you should follow the instructions in the information provided by your broker or nominee to change your vote before the meeting.

Written notices of revocation and other communications with respect to the revocation of proxies should be addressed as follows: Corporate Secretary, Chicago Bridge & Iron Company N.V., Prinses Beatrixlaan 35, 2595 AK The Hague, The Netherlands.

If you attend the CB&I Special General Meeting or vote your shares using the enclosed proxy card or voting instruction form (including any telephone or Internet voting procedures provided), your shares will be counted as present, even if you abstain from voting on a particular matter. Broker non-votes (i.e., shares held by brokers and other nominees as to which they have not received voting instructions from the beneficial owners and lack the discretionary authority to vote on a proposed resolution) will not be counted as present.

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If you are a shareholder of record of shares of CB&I Common Stock and your proxy card is signed and returned without voting instructions, it will be voted according to the recommendations of the CB&I Boards.

If you are the beneficial owner, but not the holder of record, of shares of CB&I Common Stock and fail to provide voting instructions, your broker or other holder of record may not vote on the proposals and no votes will be cast on your behalf with respect to those matters.

Failures to vote by CB&I shareholders that attend the CB&I Special General Meeting in person or by proxy, failures to vote by CB&I shareholders that do not attend the CB&I Special General Meeting in person or by proxy, abstentions and broker non-votes are not considered votes cast and therefore will have no effect on the outcome of the proposals; provided, that if the Articles Amendment Resolution is not adopted at the CB&I Special General Meeting and there is a person that alone or together with a group (beneficially) holds more than fifteen percent (15%) of the issued and outstanding share capital of CB&I at the time of the CB&I Special General Meeting, failures to vote by CB&I shareholders, whether or not they attend the CB&I Special General Meeting in person or by proxy, abstentions and broker non-votes will have the same effect as votes “AGAINST” the adoption of the Merger Resolution.

If you are not a shareholder of record registered in the CB&I Share Register, a usufructuary to whom voting rights accrue or pledgee to whom voting rights accrue, you may not attend the CB&I Special General Meeting without the invitation of the chairman of the CB&I Supervisory Board.

If you are the beneficial owner of shares, but not the holder of record, you should refer to the instructions provided by your broker or nominee for further information.

No guests will be admitted, except for guests invited by CB&I.

Registration will begin at [—] a.m. local time, and the CB&I Special General Meeting will begin promptly at [—] a.m. local time. Please note that you may be asked to present valid government-issued photo identification, such as a valid driver’s license or passport, when you check in for registration. No cameras, recording equipment or other electronic devices will be allowed to be brought into the meeting room by attendees.

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If your shares are held in the name of a bank, broker, trust company or other nominee, please instruct your nominee to vote your shares by following the instructions you receive from your nominee.

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RISK FACTORS

Before deciding how to vote (if you are a CB&I shareholder or a McDermott stockholder), or to tender your shares in the Exchange Offer (if you are a CB&I shareholder), you should carefully review and consider the risks described below, those described in the section entitled “Cautionary Statement Regarding Forward-Looking Statements” and the other information contained in this document or in the documents that McDermott and CB&I incorporate by reference into this document, particularly the risk factors set forth in the documents of McDermott and CB&I incorporated by reference into this document. In addition, you should read and consider the risks associated with each of the businesses of McDermott and CB&I because these risks will also affect McDermott, as the combined business, following completion of the Combination. See the section entitled “Where You Can Find More Information.” In addition to the risks set forth below, new risks may emerge from time to time and it is not possible to predict all risk factors, nor can McDermott or CB&I assess the impact of all factors on the Combination and the combined business following the Combination or the extent to which any factor or combination of factors may cause actual results to differ materially from those contained in or implied by any forward-looking statements.

Risks Relating to the Combination

The Exchange Offer Ratio is fixed and will not be adjusted in the event of any change in either CB&I or McDermott’s stock price.

In the Exchange Offer (as defined in the Business Combination Agreement, dated as of December 18, 2017, by and among McDermott, CB&I and the other parties thereto (as it may be amended or supplemented from time to time, the “Business Combination Agreement”)), CB&I shareholders will be offered to exchange each of their issued and outstanding shares of CB&I common stock, par value EUR 0.01 per share (“CB&I Common Stock”) for 2.47221 shares of McDermott common stock, par value $1.00 per share (“McDermott Common Stock”) or, if the McDermott Reverse Stock Split (as defined herein) has occurred, 0.82407 shares of McDermott Common Stock, plus cash in lieu of any fractional shares (collectively, the “Per Share Consideration”). Additionally, pursuant to the transactions contemplated by the Business Combination Agreement, CB&I shareholders that do not tender their shares of CB&I Common Stock in the Exchange Offer will, if the Combination is completed, ultimately receive the same Per Share Consideration, subject to applicable withholding taxes, including Dutch dividend withholding tax (the “Dutch Dividend Withholding Tax”) under the Dividend Withholding Tax Act 1965 (Wet op de dividendbelasting 1965) to the extent the Liquidation Distribution (as defined herein) exceeds the average paid-in capital recognized for Dutch dividend withholding tax purposes of the shares of CB&I Newco common stock (“CB&I Newco Common Stock”). The Exchange Offer Ratio is fixed in the Business Combination Agreement and will not be adjusted for changes in the market price of either CB&I Common Stock or McDermott Common Stock. As such, the value of the Per Share Consideration will depend in part on the price per share of McDermott Common Stock at the time the Exchange Offer and the Combination (as defined in the Business Combination Agreement) are completed. Changes in the price of McDermott Common stock prior to the expiration of the Exchange Offer and the completion of the Combination will affect the market value of the Per Share Consideration that CB&I shareholders will become entitled to receive in the Combination. Neither party is permitted to abandon the Combination or terminate the Business Combination Agreement solely because of changes in the market price of either party’s common stock. Stock price changes may result from a variety of factors (many of which are beyond CB&I’s or McDermott’s control), including:

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The price of McDermott Common Stock at the closing of the Combination may vary from its price on the date the Business Combination Agreement was executed, on the date of this document and on the date of the CB&I Special General Meeting. As a result, the market value represented by the Exchange Offer Ratio will also vary. For example, based on the range of closing prices of McDermott Common Stock during the period from December 18, 2017 (the last trading day before the public announcement of the Combination), through March 1, 2018 (the most recent practicable trading day before the date of this document), the Exchange Offer Ratio represented a market value ranging from a low of $16.14 to a high of $22.20 for each share of CB&I Common Stock.

Because the date that the Combination is completed will be later than the date of the CB&I Special General Meeting, at the time of the CB&I Special General Meeting, CB&I shareholders will not know the exact market value of the shares of McDermott Common Stock that they will receive upon completion of the Combination.

If the price of McDermott Common Stock declines between the date of the CB&I Special General Meeting and the completion of the Combination, including for any of the reasons described above, CB&I shareholders will receive shares of McDermott Common Stock that have a market value upon completion of the Combination that is less than the market value calculated pursuant to the Exchange Offer Ratio on the date of the CB&I Special General Meeting. Therefore, while the number of shares of McDermott Common Stock to be issued and delivered in exchange for each share of CB&I Common Stock is fixed, CB&I shareholders cannot be sure of the market value of the shares of McDermott Common Stock they will receive upon completion of the Combination. In addition, the market value of the shares of McDermott Common Stock that CB&I shareholders will be entitled to receive in the Combination also will continue to fluctuate after the completion of the Combination and CB&I shareholders could lose the value of their investment in McDermott Common Stock.

The market price for McDermott Common Stock may be affected by factors different from those that historically have affected the market price of CB&I Common Stock and McDermott Common Stock individually.

Upon completion of the Combination, CB&I shareholders will become McDermott stockholders. McDermott’s business differs from that of CB&I, and accordingly the results of operations of McDermott will be affected by certain factors that are different from those currently affecting the results of operations of CB&I and currently affecting the results of operations of McDermott individually. For a discussion of the businesses of McDermott and CB&I and of some important factors to consider in connection with those businesses, see the section entitled “Where You Can Find More Information” for the location of information incorporated by reference into this document.

CB&I shareholders will have a significantly reduced ownership and voting interest after the Combination and will exercise less influence over management.

Immediately after the completion of the Combination, it is expected that CB&I shareholders, who collectively own 100% of CB&I, will own approximately 47% of McDermott based on the number of shares of CB&I Common Stock and McDermott Common Stock outstanding, assuming all CB&I shareholders participate in the Exchange Offer (such that their share ownership would not be reduced as a result of withholding for the Dutch Dividend Withholding Tax). Consequently, CB&I shareholders will have less influence over the management and policies of McDermott than they currently have over the management and policies of CB&I.

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McDermott stockholders will have a significantly reduced ownership and voting interest after the Combination and will exercise less influence over management.

Immediately after the completion of the Combination, it is expected that McDermott stockholders, who collectively own 100% of McDermott, will own approximately 53% of McDermott based on the number of shares of CB&I Common Stock and McDermott Common Stock outstanding, assuming all CB&I shareholders participate in the Exchange Offer (such that their share ownership would not be reduced as a result of withholding for the Dutch Dividend Withholding Tax). Consequently, McDermott stockholders will have less influence over the management and policies of McDermott following completion of the Combination than they currently have over the management and policies of McDermott.

The unaudited pro forma combined financial statements included in this document are presented for illustrative purposes only and the actual financial condition and results of operations of McDermott following the Combination may differ materially.

The unaudited pro forma combined financial statements contained in this document are presented for illustrative purposes only, are based on various adjustments, assumptions and preliminary estimates, and may not be an indication of McDermott’s financial condition or results of operations following the Combination for several reasons. The actual financial condition and results of operations of McDermott following the Combination may not be consistent with, or evident from, these unaudited pro forma combined financial statements. In addition, the assumptions used in preparing the unaudited pro forma financial information may not prove to be accurate, and other factors may affect McDermott’s financial condition or results of operations following the Combination. Any potential decline in McDermott’s financial condition or results of operations may cause significant variations in the price of McDermott Common Stock. For more information, see the Unaudited Pro Forma Financial Statements included in this document.

The fairness opinions obtained by the McDermott Board and the CB&I Boards from their respective financial advisors will not reflect changes in circumstances between signing the Business Combination Agreement and the completion of the Combination.

Changes in the operations and prospects of McDermott or CB&I, general market and economic conditions and other factors that may be beyond the control of McDermott or CB&I, and on which the fairness opinions were based, may alter the value of McDermott or CB&I or the price of shares of McDermott Common Stock or shares of CB&I Common Stock by the time the Combination is completed. In particular, the forward-looking financial information provided by McDermott and CB&I to their financial advisors at the time of such opinions did not reflect the impact of recent U.S. tax legislation (informally known as the Tax Cuts and Jobs Act), enacted on December 22, 2017, which, among other things, decreased the U.S. corporate income tax rate from 35% to 21%, before state and local income taxes. The opinions do not speak as of the time the Combination will be completed or as of any date other than the dates of such opinions. The opinions are included as Annexes B, C and D to this document. For a description of the opinions that the McDermott Board received from its financial advisors, see the sections entitled “The Combination—Opinions of McDermott’s Financial Advisors” beginning on page 72. For a description of the opinion that the CB&I Boards received from their financial advisor, see the section entitled “The Combination—Opinion of CB&I’s Financial Advisor” beginning on page 98.

CB&I’s directors and executive officers have interests in the Combination that may be different from, and in addition to, the interests of other CB&I shareholders.

Executive officers of CB&I negotiated the terms of the Business Combination Agreement with their counterparts at McDermott. In considering this fact and the other information contained in this document, you should be aware that CB&I’s directors and executive officers are parties to agreements or participants in other arrangements that give them interests in the Combination that may be different from, or conflict with, the interests of the other shareholders of CB&I, which could create conflicts of interest with other shareholders in

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their determinations to recommend the Combination. These interests include, but are not limited to, the fact that: (1) executive officers and directors are party to certain agreements that provide for the vesting of equity awards (estimated total value for all officers and directors: $30.2 million) in connection with the Combination; (2) certain executive officers are eligible for severance benefits under their change in control agreements upon certain qualifying terminations of employment (estimated total value for all executive officers: $28.4 million); and (3) certain executive officers are eligible to receive a retention bonus in connection with the transaction (estimated total value for all executive officers: $805,834). The CB&I Supervisory Board and the CB&I Management Board (together, the “CB&I Boards”) were aware of these interests and considered them, among other matters, in approving the Business Combination Agreement and the transactions contemplated thereby and making their recommendation that CB&I’s shareholders vote in favor of the proposals for resolution at the CB&I Special General Meeting. CB&I shareholders should consider these interests in voting on the proposals. See the sections entitled “The Combination—Interests of Certain Persons in the Combination—Chicago Bridge & Iron Company N.V.” for additional details regarding these interests.

McDermott’s directors and executive officers have interests in the Combination that may be different from, and in addition to, the interests of other McDermott stockholders.

Executive officers of McDermott negotiated the terms of the Business Combination Agreement with their counterparts at CB&I. In considering this fact and the other information contained in this document, you should be aware that McDermott’s directors and executive officers are parties to agreements or participants in other arrangements that give them interests in the Combination that may be different from, or in addition to, the interests of the other stockholders of McDermott, which could create conflicts of interest in their determinations to recommend the Combination. The McDermott Board of Directors (the “McDermott Board”) was aware of these interests and considered them, among other matters, in approving the Business Combination Agreement and the transactions contemplated thereby and making its recommendation that McDermott’s stockholders vote in favor of the proposals on the agenda at the McDermott Special Meeting. McDermott stockholders should consider these interests in voting on the proposals. See the section entitled “The Combination—Interests of Certain Persons in the Combination—McDermott International, Inc.” for additional details regarding these interests.

McDermott and CB&I will be subject to business uncertainties and certain operating restrictions until completion of the Combination.

In connection with the pending Combination, some of the suppliers and customers of CB&I and/or McDermott may delay or defer sales and contracting decisions, which could negatively impact revenues, earnings and cash flows regardless of whether the Combination is completed. Additionally, CB&I and McDermott have each agreed in the Business Combination Agreement to refrain from taking certain actions with respect to their business and financial affairs during the pendency of the Combination, which restrictions could be in place for an extended period of time if completion of the Combination is delayed and could adversely impact CB&I’s and McDermott’s ability to execute certain of their business strategies and their financial condition, results of operations or cash flows. See the section entitled “The Business Combination Agreement—Conduct of Business Pending the Exchange Offer Effective Time” for a description of the restrictive covenants to which each of McDermott and CB&I is subject.

CB&I and McDermott may be unable to attract and retain key employees during the pendency of the Combination.

In connection with the pending Combination, current and prospective employees of CB&I or McDermott may experience uncertainty about their future roles with the combined business following the Combination, which may materially adversely affect the ability of CB&I and McDermott to attract and retain key personnel during the pendency of the Combination. Key employees may depart because of issues relating to the uncertainty and difficulty of integration or a desire not to remain with the combined business following the Combination.

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Accordingly, no assurance can be given that CB&I or McDermott will be able to attract and retain key employees to the same extent that CB&I or McDermott, as applicable, has been able to in the past.

The ability of CB&I and McDermott to complete the Combination is subject to the approval of CB&I shareholders and the McDermott stockholders, certain closing conditions and the receipt of consents and approvals from government entities which may impose conditions that could adversely affect CB&I or McDermott or cause the Combination to be abandoned.

The Business Combination Agreement contains certain closing conditions, including approval of certain proposals by CB&I shareholders and McDermott stockholders, the absence of injunctions or other legal restrictions, the availability of financing related to the Combination and that no material adverse effect shall have occurred with respect to either company.

In addition, CB&I and McDermott will be unable to complete the Combination until consent is received from the Federal Antimonopoly Service of the Russian Federation, which may impose certain requirements or obligations as conditions for approval. The Business Combination Agreement may require CB&I and/or McDermott to accept conditions from such regulator that could adversely impact the combined business. If this regulatory clearance is not received, then neither McDermott nor CB&I will be obligated to complete the Combination.

We can provide no assurance that the various closing conditions will be satisfied and that the necessary approvals will be obtained, or that any required conditions will not materially adversely affect the combined business following the Combination. In addition, we can provide no assurance that these conditions will not result in the abandonment or delay of the Combination.

Failure to complete the Combination, or failure to complete the Combination in the anticipated timeframe, could negatively impact CB&I and McDermott.

If the Combination is not completed, the ongoing businesses and the market price of the common stock of CB&I and/or McDermott may be adversely affected and CB&I and McDermott will be subject to several risks, including CB&I being required, under certain circumstances, to pay McDermott a termination fee of $60 million; McDermott being required, under certain circumstances, to pay CB&I a termination fee of $60 million; CB&I or McDermott having to pay certain costs relating to the Combination; and diverting the focus of management from pursuing other opportunities that could be beneficial to each of CB&I and McDermott, in each case, without realizing any of the benefits which might have resulted had the Combination been completed.

Additionally, completion of the Combination is a requirement of certain of CB&I’s indebtedness agreements. There is no guarantee that the Combination will be completed or will be completed within the timeline required by CB&I’s indebtedness agreements. The timeline will be affected by events outside of CB&I’s and McDermott’s control, such as the regulatory approval mentioned above, availability of financing related to the Combination or third party consents, which may be delayed or may not be obtained on acceptable terms. The failure to consummate the Combination within the prescribed timeframe would result in a default under CB&I’s debt agreements, and CB&I’s debt becoming immediately due, unless further amendments or waivers are obtained.

The Business Combination Agreement contains restrictions on the ability of each of CB&I and McDermott to pursue other alternatives to the Combination.

The Business Combination Agreement contains non-solicitation provisions that, subject to limited exceptions, restrict the ability of each of CB&I and McDermott to solicit, initiate or knowingly encourage or facilitate any competing acquisition proposal. Further, subject to limited exceptions, consistent with applicable law, the Business Combination Agreement provides that the CB&I Boards and the McDermott Board will not withdraw, modify or qualify, or propose publicly to withhold, withdraw, modify or qualify, in any manner adverse to the other party or its affiliates its recommendation that its shareholders or stockholders, as applicable, vote in favor

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