As filed with the U.S. Securities and Exchange Commission on February 1 , 2019

Registration No. 333- 229464

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

Bristol-Myers Squibb Company
(Exact name of registrant as specified in its charter)

430 East 29th Street, 14th Floor, New York, New York 10016
(212) 546-4000
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

At the special meeting of the stockholders of Celgene, Celgene stockholders will be asked to vote on (i) a proposal to adopt the merger agreement, (ii) a proposal to approve the adjournment from time to time of the Celgene special meeting if necessary to solicit additional proxies if there are not sufficient votes to adopt the merger agreement at the time of the Celgene special meeting or any adjournment or postponement thereof, and (iii) a proposal to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger.

Celgene’s board of directors unanimously determined that the merger agreement and the transactions contemplated by the merger agreement, including the merger, are advisable, fair to and in the best interests of Celgene and its stockholders and unanimously recommends that Celgene stockholders vote (i) “FOR” the adoption of the merger agreement, (ii) “FOR” the approval of the adjournment from time to time of the Celgene special meeting if necessary to solicit additional proxies if there are not sufficient votes to adopt the merger agreement at the time of the Celgene special meeting or any adjournment or postponement thereof, and (iii) “FOR” the proposal to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger.

Bristol-Myers Squibb expects to issue up to approximately 701,024,507 shares of its common stock and up to approximately 701,024,507 CVRs to Celgene stockholders in the merger. In addition, shares of Bristol-Myers Squibb common stock and CVRs may be issued from time to time following the effective time of the merger to holders of Celgene equity awards on the terms set forth in the merger agreement. See “The Merger Agreement—Treatment of Celgene Equity Awards” beginning on page 174 of the accompanying joint proxy statement/prospectus for a more detailed explanation. Based on the number of shares of Bristol-Myers Squibb common stock outstanding as of January 24, 2019, and the number of shares of Celgene common stock outstanding as of January 29, 2019, immediately following completion of the merger, Bristol-Myers Squibb stockholders immediately prior to the completion of the merger are expected to own approximately 69% of the outstanding shares of Bristol-Myers Squibb common stock and former Celgene stockholders are expected to own approximately 31% of the outstanding shares of Bristol-Myers Squibb common stock.

The accompanying joint proxy statement/prospectus provides important information regarding the Bristol-Myers Squibb and Celgene special meetings and a detailed description of the merger agreement, the merger, the issuance of shares of Bristol-Myers Squibb common stock and CVRs in the merger, the adjournment proposals and the proposal to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger. We urge you to read carefully and in its entirety the accompanying joint proxy statement/prospectus (including the annexes and any documents incorporated by reference into the accompanying joint proxy statement/prospectus). Please pay particular attention to the section entitled “Risk Factors” beginning on page 38 of the accompanying joint proxy statement/prospectus. You can also obtain information about Bristol-Myers Squibb and Celgene from documents that Bristol-Myers Squibb and Celgene previously have filed with the U.S. Securities and Exchange Commission.

For a discussion of the material U.S. federal income tax consequences of the merger, see “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences” beginning on page 164 of the accompanying joint proxy statement/prospectus.

Whether or not you expect to attend your company’s special meeting, the details of which are described in the accompanying joint proxy statement/prospectus, please immediately submit your proxy by telephone, by the Internet or by completing, signing, dating and returning your signed proxy card(s) in the enclosed prepaid return envelope so that your shares may be represented at the applicable special meeting.

If Bristol-Myers Squibb stockholders have any questions or require assistance in voting their shares of Bristol-Myers Squibb stock, they should call MacKenzie Partners, Inc., Bristol-Myers Squibb’s proxy solicitor for its special meeting, toll-free at (800) 322-2885 or collect at (212) 929-5500.

If Celgene stockholders have any questions or require assistance in voting their shares of Celgene common stock, they should call Innisfree M&A Incorporated, Celgene’s proxy solicitor for its special meeting, toll-free at (877) 750-9497 or (412) 232-3651 for international callers. Banks and brokers may call collect at (212) 750-5833.

We hope to see you at the applicable special meeting and look forward to the successful completion of the merger.

On behalf of the boards of directors of Bristol-Myers Squibb and Celgene, thank you for your consideration and continued support.

Sincerely,	Sincerely,
Giovanni Caforio, M.D. Chairman of the Board of Directors and Chief Executive Officer of Bristol-Myers Squibb	Mark J. Alles Chairman of the Board of Directors and Chief Executive Officer of Celgene

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

The accompanying joint proxy statement/prospectus is dated February 1, 2019 and is first being mailed to Bristol-Myers Squibb stockholders and Celgene stockholders on or about February 22, 2019.

430 East 29 ^th Street, 14 ^th Floor
New York, New York 10016
(212) 546-4000

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
OF BRISTOL-MYERS SQUIBB COMPANY
TO BE HELD ON F RIDAY , A PRIL 12 , 2019
10:00 A . M . , E ASTERN T IME

To the Stockholders of Bristol-Myers Squibb Company:

NOTICE IS HEREBY GIVEN that a special meeting of stockholders of Bristol-Myers Squibb Company, a Delaware corporation, which is referred to in this notice as Bristol-Myers Squibb, will be held at the offices of Kirkland & Ellis LLP located at 601 Lexington Avenue, New York, New York 10022 , on Friday , April 1 2 , 2019, at 10:00 a.m. , Eastern Time, for the following purposes:

Bristol-Myers Squibb’s board of directors has fixed the close of business on March 1, 2019 as the record date for the determination of the stockholders entitled to vote at the Bristol-Myers Squibb special meeting or any adjournment or postponement thereof. Only stockholders of record at the record date are entitled to notice of, and to vote at, the Bristol-Myers Squibb special meeting or any adjournment or postponement thereof. Bristol-Myers Squibb anticipates commencing its solicitation of proxies on or about February 22, 2019. Bristol-Myers Squibb will continue to solicit proxies until the date of the Bristol-Myers Squibb special meeting. All stockholders of record as of that date are cordially invited to attend the special meeting in person. If you plan to attend the Bristol-Myers Squibb special meeting, admission will be by ticket only. A form of government-issued photograph identification will be required to enter the meeting. If you are a registered stockholder (your shares are held in your name), you should bring the top portion of the proxy card, which will serve as your admission ticket.

If you are a beneficial owner (your shares are held in the name of a bank, broker or other holder of record) and plan to attend the meeting, you can obtain an admission ticket in advance by writing to Shareholder Services, 430 East 29 ^th Street, 14 ^th Floor, New York, New York 10016. Please be sure to enclose proof of ownership, such as a bank or brokerage account statement. Stockholders who do not obtain tickets in advance may obtain them upon verification of ownership at the Registration Desk on the day of the special meeting.

Your vote is very important, regardless of the number of shares of Bristol-Myers Squibb stock that you own. Approval of the issuance of shares of Bristol-Myers Squibb common stock in the merger requires the affirmative vote of at least a majority of the votes cast by holders of outstanding shares of Bristol-Myers Squibb

stock at a duly called and held meeting of Bristol-Myers Squibb’s stockholders at which a quorum is present. Approval of the adjournment proposal requires the affirmative vote of a majority of the votes present at the Bristol-Myers Squibb special meeting by holders of shares of Bristol-Myers Squibb stock entitled to vote (whether or not a quorum is present).

Bristol-Myers Squibb’s board of directors determined that the merger agreement and the transactions contemplated by the merger agreement, including the merger and the issuance of shares of Bristol-Myers Squibb common stock in the merger, are advisable, fair to and in the best interests of Bristol-Myers Squibb and its stockholders and unanimously recommends that Bristol-Myers Squibb stockholders vote (i) “FOR” the approval of the issuance of shares of Bristol-Myers Squibb common stock in the merger and (ii) “FOR” the approval of the adjournment from time to time of the Bristol-Myers Squibb special meeting if necessary to solicit additional proxies if there are not sufficient votes at the time of the Bristol-Myers Squibb special meeting, or any adjournment or postponement thereof, to approve the issuance of shares of Bristol-Myers Squibb common stock in the merger.

By Order of the Board of Directors,

Giovanni Caforio, M.D.
Chairman of the Board of Directors and Chief Executive Officer
New York, New York
February 1, 2019

IMPORTANT INFORMATION IF YOU PLAN TO ATTEND THE BRISTOL-MYERS SQUIBB SPECIAL MEETING IN PERSON:

A form of government-issued photograph identification will be required to enter the meeting.

If you hold your shares of Bristol-Myers Squibb stock through a brokerage account (in “street name”), you will also need an account statement or letter from the nominee indicating that you were the beneficial owner of the shares at the record date to be admitted to the Bristol-Myers Squibb special meeting.

Large bags, backpacks, briefcases, cameras, recording equipment and other electronic devices will not be permitted in the meeting, and attendees will be subject to security inspections. We will provide, upon request, wireless headsets for hearing amplification.

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE BRISTOL-MYERS SQUIBB SPECIAL MEETING IN PERSON, WE URGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY COMPLETING, SIGNING AND DATING THE ENCLOSED BRISTOL-MYERS SQUIBB PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. IF YOU ATTEND THE BRISTOL-MYERS SQUIBB SPECIAL MEETING IN PERSON AND WISH TO VOTE YOUR SHARES OF BRISTOL-MYERS SQUIBB STOCK AT THE BRISTOL-MYERS SQUIBB SPECIAL MEETING, YOU MAY DO SO AT ANY TIME PRIOR TO THE CLOSING OF THE POLLS AT THE BRISTOL-MYERS SQUIBB SPECIAL MEETING. You may revoke your proxy or change your vote for shares of Bristol-Myers Squibb stock you hold directly in your name by (i) signing another proxy card with a later date and delivering it to Broadridge before the date of the Bristol-Myers Squibb special meeting (we recommend you mail your proxy by April 4, 2019 to ensure timely receipt of your proxy), (ii) submitting revised votes over the Internet or by telephone before 11:59 p.m., Eastern Time, on Monday, April 8, 2019 for shares in employee benefit plans or on Thursday, April 11, 2019 for all other shares, or (iii) attending the Bristol-Myers Squibb special meeting in person and voting your shares of Bristol-Myers Squibb stock at the Bristol-Myers Squibb special meeting. If your shares of Bristol-Myers Squibb stock are held in the name of a bank, broker or other nominee holder of record, please follow the instructions on the voting instruction form furnished to you by such record holder.

The accompanying joint proxy statement/prospectus contains a detailed description of the merger, the merger agreement and the other matters to be considered at the meeting. We urge you to read carefully the accompanying joint proxy statement/prospectus, including all documents incorporated by reference into the accompanying joint proxy statement/prospectus, and its annexes, in their entirety. If you have any questions concerning the merger agreement, the merger, the issuance of shares of Bristol-Myers Squibb common stock or the CVRs in the merger, the adjournment proposal, the Bristol-Myers Squibb special meeting or the accompanying joint proxy statement/prospectus (or any other information contained therein), would like additional copies of the accompanying joint proxy statement/prospectus or need help voting your shares of Bristol-Myers Squibb stock, please contact:

MacKenzie Partners, Inc.
1407 Broadway, 27 ^th Floor
New York, New York 10018
Telephone (Toll-Free): (800) 322-2885
Telephone (Collect): (212) 929-5500
Email: proxy@mackenziepartners.com
   
or
   
Bristol-Myers Squibb Company
430 East 29 ^th Street, 14 ^th Floor
New York, New York 10016
Attention: Corporate Secretary
Telephone: (212) 546-3309

Celgene Corporation
86 Morris Avenue
Summit, New Jersey 07901
(908) 673-9000

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS OF
CELGENE CORPORATION
TO BE HELD ON F RIDAY , A PRIL 12 , 2019
10:00 A.M. , E ASTERN T IME

To the Stockholders of Celgene Corporation:

NOTICE IS HEREBY GIVEN that a special meeting of stockholders of Celgene Corporation, a Delaware corporation, which is referred to in this notice as Celgene, will be held at the offices of Wachtell, Lipton, Rosen & Katz located at 51 West 52 ^nd Street, New York, New York 10019, on Friday , April 12 , 2019, at 10:00 a.m. , Eastern Time, for the following purposes:

The holders of record of shares of Celgene common stock, par value $0.01 per share, which are referred to in this notice as shares of Celgene common stock, at the close of business on March 1, 2019 are entitled to notice of and to vote at the Celgene special meeting or any adjournment or postponement thereof. Celgene anticipates commencing its solicitation of proxies on or about February 22, 2019. Celgene will continue to solicit proxies until the date of the Celgene special meeting.

If you hold shares of Celgene common stock in your name at the record date and plan to attend the Celgene special meeting, because of security procedures, you will need to obtain an admission ticket in advance. Tickets will be available to registered and beneficial owners. You can print your own tickets and you must bring them to the meeting to gain access. Tickets can be printed by accessing Shareholder Meeting Registration at www.ProxyVote.com and following the instructions provided (you will need the 16 digit number included on your proxy card or voter instruction form). If you are unable to print your tickets, please contact Celgene’s Corporate Secretary at 1-908-673-9000. Requests for admission tickets will be processed in the order in which they are received and must be submitted no later than 11:59 p.m. (Eastern Time) on April 11, 2019. Please note that seating is limited and requests for tickets will be accepted on a first-come, first-served basis. If you received your special meeting materials electronically and wish to attend the meeting, please follow the instructions provided for attendance. If you are attending the Celgene special meeting in person, you will be required to present valid, government-issued photo identification, such as a driver’s license or passport, and an admission ticket to be admitted to the Celgene special meeting.

Adoption of the merger agreement requires the affirmative vote, in person or by proxy, of the holders of a majority of the shares of Celgene common stock outstanding and entitled to vote thereon. Approval of the

adjournment proposal requires the affirmative vote of a majority of the votes present at the Celgene special meeting by holders of shares of Celgene common stock (whether or not a quorum, as defined under Celgene’s by-laws, is present). Approval of the proposal to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger requires the affirmative vote of a majority of the votes cast at the Celgene special meeting by holders of shares of Celgene common stock (assuming a quorum, as defined under Celgene’s by-laws, is present).

Celgene’s board of directors unanimously determined that the merger agreement and the transactions contemplated by the merger agreement (including the merger) are fair to and in the best interests of Celgene and its stockholders and unanimously recommends that Celgene stockholders vote (i) “FOR” the proposal to adopt the merger agreement, (ii) “FOR” the proposal to approve the adjournment from time to time of the Celgene special meeting if necessary to solicit additional proxies if there are not sufficient votes to adopt the merger agreement at the time of the Celgene special meeting or any adjournment or postponement thereof and (iii) “FOR” the proposal to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger.

By Order of the Board of Directors,

Mark J. Alles
Chairman of the Board of Directors and
Chief Executive Officer
Summit, New Jersey
February 1, 2019

IMPORTANT INFORMATION IF YOU PLAN TO ATTEND THE CELGENE SPECIAL MEETING IN PERSON:

If you hold your shares of Celgene common stock through a brokerage account (in “street name”), your request for an admission ticket must include proof of beneficial ownership at the record date, such as a copy of a brokerage statement reflecting stock ownership as of the record date or a letter from a bank or broker.

Please leave all weapons, cameras, audio and video recording devices and other electronic devices at home. They will not be allowed in the meeting room.

YOUR VOTE IS IMPORTANT!

WHETHER OR NOT YOU EXPECT TO ATTEND THE CELGENE SPECIAL MEETING IN PERSON, WE URGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY COMPLETING, SIGNING AND DATING THE ENCLOSED CELGENE PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. IF YOU ATTEND THE CELGENE SPECIAL MEETING IN PERSON AND WISH TO VOTE YOUR SHARES AT THE CELGENE SPECIAL MEETING, YOU MAY DO SO AT ANY TIME PRIOR TO THE CLOSING OF THE POLLS AT THE CELGENE SPECIAL MEETING. You may revoke your proxy or change your vote for shares of Celgene common stock you hold directly in your name by (i) signing another proxy card with a later date and delivering it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, New York 11717 before (i) the close of business on April 9, 2019 for shares held in the Celgene 401(k) Plan and (ii) the Celgene special meeting for all other shares, (iii) submitting revised votes over the Internet or by telephone before 11:59 p.m., Eastern Time, on (A) April 9, 2019 for shares held in the Celgene 401(k) Plan or (B) April 11, 2019 for all other shares, or (iv) attending the Celgene special meeting in person and voting your shares of Celgene common stock at the Celgene special meeting. If your shares of Celgene common stock are held in the name of a bank, broker or other nominee holder of record, please follow the instructions on the voting instruction form furnished to you by such record holder.

Celgene cannot complete the merger and the merger consideration will not be paid unless its stockholders adopt the merger agreement and the other closing conditions specified in the merger agreement are met. Because adoption of the merger agreement requires the affirmative vote of the holders of at least a majority of shares of Celgene common stock outstanding and entitled to vote thereon, a Celgene stockholder’s abstention from voting, the failure of a Celgene stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Celgene stockholder to vote will have the same effect as a vote “AGAINST” the proposal to adopt the merger agreement.

We urge you to read carefully the accompanying joint proxy statement/prospectus, including all documents incorporated by reference into the accompanying joint proxy statement/prospectus, and its annexes, in their entirety. If you have any questions concerning the merger agreement, the merger, the vote on the merger agreement, the adjournment proposal, the advisory (non-binding) proposal to approve the compensation that will or may be paid or provided by Celgene to its named executive officers in connection with the merger, the Celgene special meeting or the accompanying joint proxy statement/prospectus (or any other information contained therein), would like additional copies of the accompanying joint proxy statement/prospectus or need help voting your shares of Celgene common stock, please contact:

Innisfree M&A Incorporated
501 Madison Avenue, 20 ^th Floor
New York, New York 10022
Telephone (Toll-Free): (877) 750-9497
International Callers: (412) 232-3651
Bankers and brokers may call collect: (212) 750-5833
   
or
   
Celgene Corporation
86 Morris Avenue
Summit, New Jersey 07901
Attention: Corporate Secretary
Telephone: (908) 673-9000

Celgene is holding a special meeting of stockholders, which is referred to in this joint proxy statement/prospectus as the Celgene special meeting, in order to obtain the stockholder approval necessary to adopt the merger agreement. Adoption of the merger agreement requires the affirmative vote of holders of at least a majority of the outstanding shares of Celgene common stock entitled to vote thereon. Celgene stockholders will also be asked to approve the adjournment from time to time of the Celgene special meeting if necessary to solicit additional proxies if there are not sufficient votes to adopt the merger agreement at the time of the Celgene special meeting or any adjournment or postponement thereof, which is referred to in this joint proxy statement/prospectus as the Celgene adjournment proposal, and to approve, on an advisory (non-binding) basis, the compensation that will or may be paid or provided by Celgene to its named executive officers, whom are referred to in this joint proxy statement/prospectus as the named executive officers, in connection with the merger, which proposal is referred to in this joint proxy statement/prospectus as the Celgene compensation advisory proposal. It is important that Celgene’s stockholders vote their shares of Celgene common stock on each of these matters, regardless of the number of shares owned.

This document is being delivered to you as both a joint proxy statement of Bristol-Myers Squibb and Celgene and a prospectus of Bristol-Myers Squibb in connection with the merger, the stock issuance and the issuance of contingent value rights, which issuance is referred to in this joint proxy statement/prospectus as the CVR issuance. This document is the proxy statement by which the Bristol-Myers Squibb board of directors, which is referred to in this joint proxy statement/prospectus as the BMS Board, is soliciting proxies from Bristol-Myers Squibb stockholders to vote at the Bristol-Myers Squibb special meeting, or at any adjournment or postponement of the Bristol-Myers Squibb special meeting, on the approval of the stock issuance and the approval of the Bristol-Myers Squibb adjournment proposal. In addition, this document is the prospectus of Bristol-Myers Squibb pursuant to which Bristol-Myers Squibb will issue shares of Bristol-Myers Squibb common stock and the contingent value rights, which are referred to in this joint proxy statement/prospectus as the CVRs, to Celgene stockholders as part of the merger consideration, as described under “The Merger Agreement—Merger Consideration” beginning on page 172 of this joint proxy statement/prospectus. This document is also the proxy statement by which the Celgene board of directors, which is referred to in this joint proxy statement as the Celgene Board, is soliciting proxies from Celgene stockholders to vote at the Celgene special meeting, or at any adjournment or postponement of the Celgene special meeting, on the adoption of the merger agreement, the approval of the Celgene adjournment proposal and the approval, on an advisory (non-binding) basis, of the Celgene compensation advisory proposal.

broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Bristol-Myers Squibb stockholder to vote will have no effect on the approval of the Bristol-Myers Squibb adjournment proposal because these failures to vote are not considered “votes present.” The Celgene Board unanimously recommends that Celgene stockholders vote “FOR” the adoption of the merger agreement, “FOR” the Celgene adjournment proposal and “FOR” the Celgene compensation advisory proposal, and the BMS Board unanimously recommends that Bristol-Myers Squibb stockholders vote “FOR” the approval of the stock issuance and “FOR” the approval of the Bristol-Myers Squibb adjournment proposal.

Based on the closing price of shares of Bristol-Myers Squibb common stock on the New York Stock Exchange, which is referred to in this joint proxy statement/prospectus as the NYSE, on January 2, 2019, the last trading day prior to the announcement of the transaction, the upfront merger consideration represented approximately $102.43 in value for each share of Celgene common stock (without considering any potential CVR payout). Based on the closing price of shares of Bristol-Myers Squibb common stock on the NYSE on January 31, 2019, the most recent trading day prior to the date of this joint proxy

statement/prospectus for which this information was available, the cash and stock components of the merger consideration, which is referred to in this joint proxy statement/prospectus as the upfront merger consideration, represented approximately $99.37 in value for each share of Celgene common stock (without considering any potential CVR payout). Because Bristol-Myers Squibb will issue one share of Bristol-Myers Squibb common stock in exchange for each share of Celgene common stock, the value of the share consideration will depend on the market price of shares of Bristol-Myers Squibb common stock at the time the merger is completed. The market price of shares of Bristol-Myers Squibb common stock when Celgene stockholders receive those shares after the merger is completed will not be known at the time of the special meetings and could be greater than, less than or the same as the market price of shares of Bristol-Myers Squibb common stock on January 2, 2019, on the date of this joint proxy statement/prospectus or at the time of the special meetings or any adjournment or postponement thereof. Furthermore, there is uncertainty regarding the fair market value of the CVR and whether any payment will ultimately be realized on the CVRs. Because the exchange ratio is fixed and the market price of shares of Bristol-Myers Squibb common stock has fluctuated and will continue to fluctuate, and because of the uncertainty of the fair market value of, and the ultimate realization on, the CVRs, Celgene stockholders cannot be sure of the value of the merger consideration they will receive in the merger. See “Risk Factors—Risks Related to the Merger.”

For a more detailed description of the CVRs, see the section entitled “Description of the CVRs” beginning on page 216 of this joint proxy statement/prospectus.

Annual Report on Form 10-K for the year ended December 31, 2017, as updated by their respective Quarterly Reports on Form 10-Q, and future filings with the SEC, each of which is on file or will be filed with the SEC, which maintains a website located at http://www.sec.gov with this information, and all of which are incorporated by reference into this joint proxy statement/prospectus, as well as the section of this joint proxy statement/prospectus entitled “Risk Factors,” which sets forth certain risks and uncertainties related to the merger, risks and uncertainties to which the combined company’s business will be subject, and risks and uncertainties to which each of Bristol-Myers Squibb and Celgene, as an independent company, is subject.

The adoption of the merger agreement by Celgene stockholders is a condition to the obligations of Celgene and Bristol-Myers Squibb to complete the merger. Neither the approval of the Celgene adjournment proposal nor the approval of the Celgene compensation advisory proposal is a condition to the obligations of Celgene or Bristol-Myers Squibb to complete the merger.

The approval of the stock issuance by Bristol-Myers Squibb stockholders is a condition to the obligations of Celgene and Bristol-Myers Squibb to complete the merger. The approval of the Bristol-Myers Squibb adjournment proposal is not a condition to the obligations of Celgene or Bristol-Myers Squibb to complete the merger.

bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Celgene stockholder to vote will have no effect on the approval of this proposal except to the extent it results in there being insufficient shares present at the Celgene special meeting to establish a quorum.

If you hold shares of Celgene common stock directly in your name as a stockholder of record, you may vote via the Internet or by telephone by following the intstructions on the enclosed proxy card. In order to vote your shares via the Internet or by telephone, you will need the control number on your proxy card (which is unique to each Celgene stockholder to ensure all voting instructions are genuine and to prevent duplicate voting). Votes may be submitted via the Internet or by telephone, 24 hours a day, seven days a week, and must be received by 11:59 p.m. (Eastern Time) on (i) April 9, 2019 for shares held in the Celgene 401(k) Plan or (ii) April 11, 2019 for all other shares.

If you hold shares of Celgene common stock in “street name,” meaning through a broker, bank or other nominee holder of record, you may submit voting instructions via the Internet or by telephone only if Internet or telephone voting is made available by your broker, bank or other nominee holder of record. Please follow the voting instructions provided by your broker, bank or other nominee holder of record with these materials.

By Mail

If you hold shares of Celgene common stock directly in your name as a stockholder of record, in order to vote by mail, you may submit a proxy card. You will need to complete, sign and date your proxy card and return it using the postage-paid return envelope provided.

If you hold shares of Celgene common stock in “street name,” meaning through a broker, bank or other nominee holder of record, in order to provide voting instructions by mail you will need to complete, sign and date the voting instruction form provided by your broker, bank or other nominee holder of record with these materials and return it in the postage-paid return envelope provided. Your broker, bank or other nominee holder of record must receive your voting instruction form in sufficient time to vote your shares.

In Person

If you hold shares of Celgene common stock directly in your name as a stockholder of record, you may vote in person at the Celgene special meeting. Stockholders of record also may be represented by another person at the Celgene special meeting by executing a proper proxy designating that person and having that proper proxy be presented to the judge of election with the applicable ballot at the Celgene special meeting.

If you hold shares of Celgene common stock in “street name,” meaning through a broker, bank or other nominee holder of record, you must obtain a written legal proxy from that institution and present it to the judge of election with your ballot to be able to vote in person at the Celgene special meeting. To request a legal proxy, please contact your broker, bank or other nominee holder of record.

Please carefully consider the information contained in this joint proxy statement/prospectus. Whether or not you plan to attend the Celgene special meeting, Celgene encourages you to vote via the Internet, by telephone or by mail so that your shares will be voted in accordance with your wishes even if you later decide not to attend the Celgene special meeting.

Celgene encourages you to register your vote via the Internet, by telephone or by mail. If you attend the Celgene special meeting, you may also vote in person, in which case any votes that you previously submitted—whether via the Internet, by telephone or by mail—will be revoked and superseded by the vote that you cast at the Celgene special meeting. Your attendance at the Celgene special meeting alone will not revoke any proxy previously given. To vote in person at the Celgene special meeting, beneficial owners who hold shares in “street name” through a broker, bank or other nominee holder of record will need to contact the broker, bank or other nominee holder of record to obtain a written legal proxy to bring to the meeting. Whether your proxy is submitted via the Internet, by telephone or by mail, if it is properly completed and submitted, and if you do not revoke it prior to or at the Celgene special meeting, your shares will be voted at the Celgene special meeting in the manner specified by you, except as otherwise set forth in this joint proxy statement/prospectus.

You may vote via the Internet or by telephone until 11:59 p.m. (Eastern Time) on (i) April 9, 2019 for shares held in the Celgene 401(k) Plan or (ii) April 11 , 2019 for all other shares , or Broadridge must receive your proxy card by mail no later than the close of business on (i) April 9, 2019 for shares held in the Celgene 401(k) Plan or (ii) April 11 , 2019 for all other shares .

Under stock exchange rules, brokers, banks and other nominee holders of record are precluded from exercising their voting discretion with respect to non-routine or “significant” matters, such as the adoption of the merger agreement, the approval of the Celgene adjournment proposal and the approval of the Celgene compensation advisory proposal. As a result, absent specific instructions from the beneficial owner of shares of Celgene common stock, brokers, banks and other nominees holders of record are not empowered to vote such shares.

Broker non-votes are shares held by a broker, bank or other nominee holder of record with respect to which the broker, bank or other nominee holder of record is not instructed by the beneficial owner of such shares on how to vote on a particular proposal and the broker, bank or other nominee holder of record does not have discretionary voting power on such proposal. Because brokers, banks and other nominee holders of record do not have discretionary voting authority with respect to any of the proposals to be considered at the Celgene special meeting as described in this joint proxy statement/prospectus, if a beneficial owner of shares of Celgene common stock held in “street name” does not give voting instructions to the broker, bank or other nominee holder of record, then those shares will not be present in person or represented by proxy at the Celgene special meeting.

A beneficial owner’s failure to instruct the broker, bank or other nominee holder of record how to vote shares of Celgene common stock held in “street name” will therefore have the same effect as a vote “AGAINST” the adoption of the merger agreement. A beneficial owner’s failure to instruct the broker, bank or other nominee holder of record how to vote shares of Celgene common stock held in “street name” will have no effect on the proposal to approve the Celgene adjournment proposal or the proposal to approve, on an advisory (non-binding) basis, the Celgene compensation advisory proposal, except, with respect to the Celgene compensation advisory proposal, to the extent it results in there being insufficient shares present at the Celgene special meeting to establish a quorum.

However, if you indicate that you wish to vote against the adoption of the merger agreement and leave the other proposals blank, your shares will not be voted in favor of the Celgene adjournment proposal or the Celgene compensation advisory proposal.

If you hold shares of Bristol-Myers Squibb stock directly in your name as a stockholder of record, you may vote via the Internet at www.proxyvote.com or by telephone by calling (800) 322-2885 toll-free. In order to submit a proxy to vote via the Internet or by telephone, you will need the control number on your proxy card (which is unique to each Bristol-Myers Squibb stockholder to ensure all voting instructions are genuine and to prevent duplicate voting). Votes may be submitted via the Internet or by telephone 24 hours a day, seven days a week, and must be received by 11:59 p.m. (Eastern Time) either on Monday, April 8, 2019 for shares in employee benefit plans or on Thursday, April 11, 2019 for all other shares. Please be aware that if you vote by telephone or over the Internet, you may incur costs such as telephone and Internet access charges for which you will be responsible.

If you hold shares of Bristol-Myers Squibb stock in “street name,” meaning through a broker, bank or other nominee holder of record, you may vote via the Internet or by telephone only if Internet or telephone voting is made available by your broker, bank or other nominee holder of record. Please follow the voting instructions provided by your broker, bank or other nominee holder of record with these materials.

By Mail

If you hold shares of Bristol-Myers Squibb stock directly in your name as a stockholder of record, you may submit a proxy card to vote your shares by mail. You will need to complete, sign and date your proxy card

and return it using the postage-paid return envelope provided or return it to Broadridge. In order to ensure Broadridge’s timely receipt of your proxy card, we recommend that you mail your proxy card no later than the close of business on April 4, 2019.

If you hold shares of Bristol-Myers Squibb stock in “street name,” meaning through a broker, bank or other nominee holder of record, in order to provide voting instructions by mail, you will need to complete, sign and date the voting instruction form provided by your broker, bank or other nominee holder of record with these materials and return it in the postage-paid return envelope provided. Your broker, bank or other nominee holder of record must receive your voting instruction form in sufficient time to vote your shares.

In Person

If you hold shares of Bristol-Myers Squibb stock directly in your name as a stockholder of record, you may vote in person at the Bristol-Myers Squibb special meeting. Stockholders of record also may be represented by another person at the Bristol-Myers Squibb special meeting by executing a proper proxy designating that person and having that proper proxy be presented to the judge of election with the applicable ballot at the Bristol-Myers Squibb special meeting.

If you hold shares of Bristol-Myers Squibb stock in “street name,” meaning through a broker, bank or other nominee holder of record, you must obtain a written legal proxy from that institution and present it to the judge of election with your ballot to be able to vote in person at the Bristol-Myers Squibb special meeting. To request a legal proxy, please contact your broker, bank or other nominee holder of record.

Please carefully consider the information contained in this joint proxy statement/prospectus. Whether or not you plan to attend the Bristol-Myers Squibb special meeting, Bristol-Myers Squibb encourages you to vote via the Internet, by telephone or by mail so that your shares will be voted in accordance with your wishes even if you later decide not to attend the Bristol-Myers Squibb special meeting.

Bristol-Myers Squibb encourages you to register your vote via the Internet, by telephone or by mail. If you attend the Bristol-Myers Squibb special meeting, you may also vote in person, in which case any votes that you previously submitted—whether via the Internet, by telephone or by mail—will be revoked and superseded by the vote that you cast at the Bristol-Myers Squibb special meeting. To vote in person at the Bristol-Myers Squibb special meeting, beneficial owners who hold shares in “street name” through a broker, bank or other nominee holder of record will need to contact the broker, bank or other nominee holder of record to obtain a written legal proxy to bring to the meeting. Whether your proxy is submitted via the Internet, by phone or by mail, if it is properly completed and submitted, and if you do not revoke it prior to or at the Bristol-Myers Squibb special meeting, your shares will be voted at the Bristol-Myers Squibb special meeting in the manner specified by you, except as otherwise set forth in this joint proxy statement/prospectus.

Y ou may vote via the Internet or by telephone until 11:59 p.m., Eastern Time, either on Monday, April 8, 2019 for shares in employee benefit plans or on Thursday, April 11, 2019 for all other shares. We recommend you mail your proxy by April 4, 2019 to ensure timely receipt of your proxy .

Broker non-votes are shares held by a broker, bank or other nominee holder of record that are present in person or represented by proxy at the Bristol-Myers Squibb special meeting, but with respect to which the broker, bank or other nominee holder of record is not instructed by the beneficial owner of such shares on how to vote on a particular proposal and the broker does not have discretionary voting power on such proposal. Because brokers, banks and other nominee holders of record do not have discretionary voting authority with respect to either of the proposals to be considered at the Bristol-Myers Squibb special meeting as described in this joint proxy statement/prospectus, if a beneficial owner of shares of Bristol-Myers Squibb stock held in “street name” does not give voting instructions to the broker, bank or other nominee holder of record, then those shares will not be present in person or represented by proxy at the Bristol-Myers Squibb special meeting. As a result, there will not be any broker non-votes in connection with either of the proposals to be considered at the Bristol-Myers Squibb special meeting as described in this joint proxy statement/prospectus.

However, if you indicate that you wish to vote against the approval of the stock issuance, your shares will only be voted in favor of the Bristol-Myers Squibb adjournment proposal if you indicate that you wish to vote in favor of that proposal.

Celgene stockholders may contact Innisfree M&A Incorporated at (877) 750-9497 (toll-free) or (412) 232-3651 (for international callers) to obtain directions to the location of the Celgene special meeting. Banks and brokers may call collect at (212) 750-5833.

Bristol-Myers Squibb stockholder (your shares are held in your name) and plan to attend the meeting, you should bring the top portion of the proxy card, which will serve as your admission ticket. If you are a beneficial owner (your shares are held in the name of a bank, broker or other holder of record) and plan to attend the meeting, you can obtain an admission ticket in advance by writing to Shareholder Services, Bristol-Myers Squibb Company, 430 East 29 ^th Street, 14 ^th Floor, New York, New York 10016. Please be sure to enclose proof of ownership, such as a bank or brokerage account statement. Stockholders who do not obtain tickets in advance may obtain them upon verification of ownership at the Registration Desk on the day of the special meeting.

If you are a stockholder of record at the record date for the Bristol-Myers Squibb special meeting (the close of business on March 1, 2019), you can revoke your proxy or change your vote by:

If you hold your shares in “street name” through a broker, bank or other nominee holder of record, you must contact your broker, bank or other nominee holder of record to change your vote or obtain a written legal proxy to vote your shares if you wish to cast your vote in person at the Bristol-Myers Squibb special meeting.

If you are a stockholder of record at the record date for the Celgene special meeting (the close of business on March 1, 2019), you can revoke your proxy or change your vote by:

If you hold your shares in “street name” through a broker, bank or other nominee holder of record, you must contact your broker, bank or other nominee holder of record to change your vote or obtain a written legal proxy to vote your shares if you wish to cast your vote in person at the Celgene special meeting.

Each Celgene stockholder is urged to read the discussion in the section entitled “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences” beginning on page 164 of this joint proxy statement/prospectus and to consult its tax advisor to determine the particular U.S. federal, state or local or non-U.S. income or other tax consequences to it of the merger.

If you hold shares in “street name” through a broker, bank or other nominee holder of record, please instruct your broker, bank or other nominee holder of record to vote your shares by following the instructions that the broker, bank or other nominee holder of record provides to you with these materials.

Please note that you cannot vote the shares of Bristol-Myers Squibb common stock you hold through either of the Bristol-Myers Squibb 401(k) Plans in person at the Bristol-Myers Squibb special meeting.

In addition to solicitation by mail, directors, officers and employees of Celgene or its subsidiaries may solicit proxies from stockholders by telephone, telegram, email, personal interview or other means. Celgene currently expects not to incur any costs beyond those customarily expended for a solicitation of proxies in connection with the adoption of a merger agreement. Directors, officers and employees of Celgene will not receive additional compensation for their solicitation activities, but may be reimbursed for reasonable out-of-pocket expenses incurred by them in connection with the solicitation. Brokers, dealers, commercial banks, trust companies, fiduciaries, custodians and other nominees have been requested to forward proxy solicitation materials to their customers, and such nominees will be reimbursed for their reasonable out-of-pocket expenses. Celgene will pay the costs associated with the Celgene special meeting and solicitation of proxies, including the costs of mailing the proxy materials.

Innisfree M&A Incorporated
501 Madison Avenue, 20 ^th Floor
New York, New York 10022
Telephone (Toll-Free): (877) 750-9497
International Callers: (412) 232-3651
Banks and brokers may call collect: (212) 750-5833

or

Celgene Corporation
86 Morris Avenue
Summit, New Jersey 07901
Attention: Corporate Secretary
Telephone: (908) 673-9000

MacKenzie Partners, Inc.
1407 Broadway, 27 ^th Floor
New York, New York 10018
Telephone (Toll-Free): (800) 322-2885
Telephone (Collect): (212) 929-5500
Email: proxy@mackenziepartners.com

or

Bristol-Myers Squibb Company
430 East 29 ^th Street, 14 ^th Floor
New York, New York 10016
Attention: Corporate Secretary
Telephone: (212) 546-3309

the merger. Merger Sub has not carried on any activities or operations to date, except for activities incidental to its formation and activities undertaken in connection with the merger. By operation of the merger, Merger Sub will be merged with and into Celgene, with Celgene surviving the merger as a wholly-owned subsidiary of Bristol-Myers Squibb.

The principal executive offices of Merger Sub are located at 430 East 29 ^th Street, 14 ^th Floor, New York, New York 10016; and its telephone number is (212) 546-4000.

The Merger (see page 171 )

Bristol-Myers Squibb, Merger Sub and Celgene have entered into the merger agreement. Subject to the terms and conditions of the merger agreement and in accordance with applicable law, in the merger, Merger Sub will be merged with and into Celgene, with Celgene continuing as the surviving corporation and a wholly-owned subsidiary of Bristol-Myers Squibb. Upon completion of the merger, shares of Celgene common stock will no longer be publicly traded, will be delisted from Nasdaq and deregistered under the Exchange Act.

A copy of the merger agreement is attached as Annex A to this joint proxy statement/prospectus. You should read the merger agreement carefully and in its entirety because it is the legal document that governs the merger.

Special Meeting of Stockholders of Bristol-Myers Squibb (see page 82 )

Meeting. The Bristol-Myers Squibb special meeting will be held on April 12, 2019, at the offices of Kirkland & Ellis LLP located at 601 Lexington Avenue, New York, New York 10022, at 10:00 a.m., Eastern Time. At the Bristol-Myers Squibb special meeting, Bristol-Myers Squibb stockholders will be asked to consider and vote on the following proposals:

Record Date. The BMS Board has fixed the close of business on March 1, 2019, as the record date for the determination of the stockholders entitled to notice of and to vote at the Bristol-Myers Squibb special meeting or any adjournment or postponement of the Bristol-Myers Squibb special meeting. Only Bristol-Myers Squibb stockholders of record at the record date are entitled to receive notice of, and to vote at, the Bristol-Myers Squibb special meeting or any adjournment or postponement of the Bristol-Myers Squibb special meeting. As of the close of business on January 24, 2019, there were (i) 1,632,650,807.509 shares of Bristol-Myers Squibb, $0.10 par value per share, common stock outstanding and entitled to vote at the Bristol-Myers Squibb special meeting, held by approximately 39,427 holders of record, and (ii) 3,586 shares of Bristol-Myers Squibb $2.00 convertible preferred stock outstanding and entitled to vote at the Bristol-Myers Squibb special meeting, held by approximately 141 holders of record.

Quorum. The presence at the Bristol-Myers Squibb special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of Bristol-Myers Squibb stock at the record date (the close of business on March 1, 2019) entitled to vote will constitute a quorum. Elections to abstain from voting will be deemed present at the Bristol-Myers Squibb special meeting for the purpose of determining the presence of a quorum. Shares of Bristol-Myers Squibb stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee holder of record, and shares of Bristol-Myers Squibb stock with respect to which the beneficial owner otherwise fails to vote, will not be deemed present at the Bristol-Myers Squibb special meeting for the purpose of determining the presence of a quorum. There must be a quorum for the vote on the stock issuance to be taken at the Bristol-Myers Squibb special meeting. Failure of a quorum to be present at the Bristol-Myers Squibb special meeting will necessitate an adjournment of the meeting and will subject Bristol-Myers Squibb to additional expense.

Required Vote. The affirmative vote of at least a majority of the votes cast by holders of outstanding shares of Bristol-Myers Squibb stock at a duly called and held meeting of Bristol-Myers Squibb’s stockholders at which a quorum is present is required to approve the issuance of shares of Bristol-Myers Squibb stock in connection with the merger. Bristol-Myers Squibb cannot complete the merger unless its stockholders approve the stock issuance . Under the current rules and interpretive guidance of the NYSE, “votes cast” on the stock issuance consist of votes “for” or “against,” as well as elections to abstain from voting on the stock issuance. As a result,

a Bristol-Myers Squibb stockholder’s abstention from voting on the stock issuance will have the same effect as a vote “AGAINST” the proposal. Assuming a quorum is present, the failure of a Bristol-Myers Squibb stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Bristol-Myers Squibb stockholder to vote will have no effect on the outcome of any vote to approve the stock issuance because these failures to vote are not considered “votes cast.”

Approval of the Bristol-Myers Squibb adjournment proposal, whether or not a quorum, as defined under Delaware law, is present, requires the affirmative vote of a majority of the votes present at the Bristol-Myers Squibb special meeting by Bristol-Myers Squibb stockholders entitled to vote. For purposes of the Bristol-Myers Squibb adjournment proposal, “votes present” on the proposal consist of votes “for” or “against” as well as elections to abstain from voting on the proposal. As a result, a Bristol-Myers Squibb stockholder’s abstention from voting on the Bristol-Myers Squibb adjournment proposal will have the same effect as a vote “AGAINST” the approval of the proposal. The failure of a Bristol-Myers Squibb stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Bristol-Myers Squibb stockholder to vote will have no effect on the approval of this proposal because these failures to vote are not considered “votes present.”

Stock Ownership of and Voting by Bristol-Myers Squibb Directors and Executive Officers (see page 221 ) . As of January 24, 2019, Bristol-Myers Squibb’s directors and executive officers and their affiliates beneficially owned and had the right to vote in the aggregate 1,810,875 shares of Bristol-Myers Squibb stock at the Bristol-Myers Squibb special meeting, which represents approximately less than 1% of the shares of Bristol-Myers Squibb stock entitled to vote at the Bristol-Myers Squibb special meeting. Approval of the stock issuance requires the affirmative vote of at least a majority of the votes cast by holders of outstanding shares of Bristol-Myers Squibb stock at a duly called and held meeting of Bristol-Myers Squibb’s stockholders at which a quorum is present.

Each of Bristol-Myers Squibb’s directors and executive officers is expected, as of the date of this joint proxy statement/prospectus, to vote his or her shares of Bristol-Myers Squibb stock “FOR” the stock issuance and “FOR” the Bristol-Myers Squibb adjournment proposal, although none of Bristol-Myers Squibb’s directors and executive officers has entered into any agreement requiring them to do so.

Special Meeting of Stockholders of Celgene (see page 87 )

Meeting. The Celgene special meeting will be held at the offices of Wachtell, Lipton, Rosen & Katz located at 51 West 52 ^nd Street, New York, New York 10019 on Friday, April 12, 2019, at 10:00 a.m., Eastern Time. At the Celgene special meeting, Celgene stockholders will be asked to consider and vote on the following proposals:

Record Date. A committee of the Celgene Board has fixed the close of business on March 1, 2019, as the record date for the determination of the Celgene stockholders entitled to notice of and to vote at the Celgene special meeting or any adjournment or postponement of the Celgene special meeting. Only Celgene stockholders of record at the record date are entitled to receive notice of, and to vote at, the Celgene special meeting or any adjournment or postponement of the Celgene special meeting. As of the close of business on January 29, 2019, there were 701,024,507 shares of Celgene common stock outstanding and entitled to vote at the Celgene special meeting, held by approximately 363 holders of record. Each holder of shares of Celgene common stock is entitled to one vote for each share of Celgene common stock owned at the record date.

Quorum. The presence at the Celgene special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of Celgene common stock at the record date (the close of business on March 1, 2019) and entitled to vote will constitute a quorum. Shares of Celgene common stock whose holders elect to abstain from voting will be deemed present at the Celgene special meeting for the purpose of determining the presence of a quorum. Shares of Celgene common stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee holder of record, and shares of Celgene common stock with respect

to which the beneficial owner otherwise fails to vote, will not be deemed present at the Celgene special meeting for the purpose of determining the presence of a quorum. There must be a quorum for the vote on the adoption of the merger agreement and the vote on the Celgene compensation advisory (non-binding) proposal to be taken at the Celgene special meeting. Failure of a quorum to be present at the Celgene special meeting will necessitate an adjournment of the meeting and will subject Celgene to additional expense.

Required Vote. Pursuant to Delaware law, to adopt the merger agreement, the affirmative vote of the holders of a majority of shares of Celgene common stock outstanding and entitled to vote thereon is required. Celgene cannot complete the merger and the merger consideration will not be paid unless its stockholders adopt the merger agreement and the other closing conditions specified in the merger agreement are met. Because adoption of the merger agreement requires the affirmative vote of the holders of at least a majority of shares of Celgene common stock outstanding and entitled to vote thereon, a Celgene stockholder’s abstention from voting, the failure of a Celgene stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Celgene stockholder to vote will have the same effect as a vote “AGAINST” the proposal to adopt the merger agreement.

To approve the Celgene adjournment proposal (whether or not a quorum, as defined under Celgene’s by-laws, is present), the affirmative vote of a majority of the votes present at the Celgene special meeting by holders of shares of Celgene common stock is required. For purposes of the Celgene adjournment proposal, “votes present” consist of votes “for” or “against” as well as elections to abstain from voting on the proposal. As a result, a Celgene stockholder’s abstention from voting on the Celgene adjournment proposal will have the same effect as a vote “AGAINST” the approval of the proposal. The failure of a Celgene stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Celgene stockholder to vote will have no effect on the approval of this proposal because these failures to vote are not considered “votes present.”

To approve, on an advisory (non-binding) basis, the Celgene compensation advisory proposal (assuming a quorum, as defined under Celgene’s by-laws, is present), the affirmative vote of a majority of the votes cast at the Celgene special meeting by holders of shares of Celgene common stock is required. For purposes of the Celgene compensation advisory proposal, “votes cast” means votes “for” or “against” the proposal. As a result, a Celgene stockholder’s abstention from voting will have no effect on the outcome of any vote to approve, on an advisory (non-binding) basis, the Celgene compensation advisory proposal. The failure of a Celgene stockholder who holds his or her shares in “street name” through a broker, bank or other nominee holder of record to give voting instructions to that broker, bank or other nominee holder of record or any other failure of a Celgene stockholder to vote will have no effect on the outcome of any vote to approve, on an advisory (non-binding) basis, the Celgene compensation advisory proposal, except to the extent it results in there being insufficient shares present at the Celgene special meeting to establish a quorum.

Stock Ownership of and Voting by Celgene Directors and Executive Officers (see page 89 ) . As of the close of business on January 29, 2019), Celgene’s directors and executive officers and their affiliates beneficially owned and had the right to vote in the aggregate 595,296 shares of Celgene common stock at the Celgene special meeting, which represents approximately less than 1% of the shares of Celgene common stock entitled to vote at the Celgene special meeting.

Each of Celgene’s directors and executive officers is expected, as of the date of this joint proxy statement/prospectus, to vote his or her shares of Celgene common stock “FOR” the proposal to adopt the merger agreement, “FOR” the Celgene adjournment proposal and “FOR” the Celgene compensation advisory proposal, although none of Celgene’s directors or executive officers has entered into any agreement requiring them to do so.

What Celgene Stockholders Will Receive in the Merger (see page 105 )

If the merger is completed, Celgene stockholders, other than holders of excluded stock and dissenting stock, will be entitled to receive, in exchange for each share of Celgene common stock that they own immediately prior to the completion of the merger, $50.00 in cash without interest thereon, one share of Bristol-Myers Squibb common stock and one CVR.

The exchange ratio is fixed, which means that it will not change between now and the date of the merger, regardless of whether the market price of either shares of Bristol-Myers Squibb common stock or shares of

Celgene common stock changes. Therefore, the value of the share consideration will depend on the market price of shares of Bristol-Myers Squibb common stock at the time Celgene stockholders receive shares of Bristol-Myers Squibb common stock in the merger. Based on the closing price of a share of Bristol-Myers Squibb common stock on the NYSE on January 2, 2019, the last trading day prior to announcement of the transaction between Bristol-Myers Squibb and Celgene, the upfront merger consideration represented approximately $102.43 in value for each share of Celgene common stock (without considering any potential CVR payout). Based on the closing price of a share of Bristol-Myers Squibb common stock on the NYSE on January 31, 2019, the most recent trading day prior to the date of this joint proxy statement/prospectus for which this information was available, the upfront merger consideration represented approximately $99.37 in value for each share of Celgene common stock (without considering any potential CVR payout). The market price of shares of Bristol-Myers Squibb common stock has fluctuated since the date of the announcement of the merger agreement and will continue to fluctuate from the date of this joint proxy statement/prospectus to the date of the Celgene special meeting and the date the merger is completed and thereafter. The market price of shares of Bristol-Myers Squibb common stock when received by Celgene stockholders after the merger is completed could be greater than, less than or the same as the market price of shares of Bristol-Myers Squibb common stock on the date of this joint proxy statement/prospectus or at the time of the Celgene special meeting or any adjournment or postponement thereof .

Treatment of Celgene Equity Awards (see page 174 )

At the effective time of the merger, each Celgene Stock Option, whether or not vested will be treated as described below.

If such Celgene Stock Option is an In-the-Money Option it will be assumed by Bristol-Myers Squibb and converted into (a) an Assumed In-the-Money Option to purchase, on the same terms and conditions as applied to each such Celgene Stock Option immediately prior to the effective time of the merger, shares of Bristol-Myers Squibb common stock, except that the number of shares of Bristol-Myers Squibb common stock, subject to such Assumed In-the-Money Options shall equal the product of (i) the number of shares of Celgene common stock that were subject to such Celgene Stock Option immediately prior to the completion of the merger, multiplied by (ii) the Equity Award Exchange Ratio (rounded down to the nearest number of whole shares of Bristol-Myers Squibb common stock) and the per-share exercise price will equal the quotient of (x) the exercise price per share of Celgene common stock at which such Celgene Stock Option was exercisable, divided by (y) the Equity Award Exchange Ratio (rounded up to the nearest whole cent), and (b) the right to receive (i) if such In-the-Money Option was vested prior to the effective time of the merger, one CVR for each share of Celgene common stock underlying such In-the-Money Option or (ii) if such In-the-Money Option was not vested immediately prior to the completion of the merger, immediately upon, and subject to, the vesting of the Assumed In-the Money Option, the Unvested Equity Award CVR Consideration. Each Assumed In-the-Money Option will continue to have the same terms and conditions as applied to the corresponding Celgene Stock Option immediately prior to the effective time of the merger.

If such Celgene Stock Option is an Out-of-the-Money Option, it will be assumed by Bristol-Myers Squibb and converted into an Assumed Out-of-the-Money Stock Option to purchase, on the same terms and conditions as applied to each such Celgene Stock Option immediately prior to the effective time of the merger, shares of Bristol-Myers Squibb common stock, except that the number of shares of Bristol-Myers Squibb common stock, subject to such Assumed Out-of-the-Money Stock Option will equal the product of (i) the number of shares of Celgene common stock that were subject to such Celgene Stock Option immediately prior to the effective time of the merger, multiplied by (ii) the Out-of-the-Money Option Exchange Ratio (rounded down to the nearest number of whole shares of Bristol-Myers Squibb common stock), and the per-share exercise price will equal the quotient of (A) the exercise price per share of Celgene common stock at which such Celgene Stock Option was exercisable, divided by (B) the Out-of-the-Money Option Exchange Ratio (rounded up to the nearest whole cent). Each Assumed Out-of-the-Money Stock Option will continue to have the same terms and conditions as applied to the corresponding Celgene Stock Option immediately prior to the effective time of the merger.

At the effective time of the merger, each Celgene RSU Award will be assumed by Bristol-Myers Squibb and converted into (i) an Assumed Restricted Unit Award that settles in a number of shares of Bristol-Myers Squibb common stock equal to the number of shares of Celgene common stock underlying the Celgene RSU Award immediately prior to the effective time of the merger multiplied by the Equity Award Exchange Ratio (rounded up to the nearest whole number of shares) and (ii) the right to receive, subject to the vesting of the Assumed

Restricted Unit Award, the Unvested Equity Award CVR Consideration. Each Assumed Restricted Unit Award will continue to have the same terms and conditions as applied to the corresponding Celgene RSU Award immediately prior to the effective time of the merger.

At the effective time of the merger, each Celgene PSU Award will be assumed by Bristol-Myers Squibb and converted into (i) an Assumed Performance Unit Award that settles in a number of shares of Bristol-Myers Squibb common stock equal to the product of the number of shares of Celgene common stock underlying the Celgene PSU Award immediately prior to the effective time of the merger (determined by deeming the applicable performance goals to be achieved at the greater of the target level and the actual level of achievement through the end of the calendar quarter immediately preceding the merger effective time) multiplied by the Equity Award Exchange Ratio (rounded up to the nearest whole number of shares), and (ii) the right to receive, subject to the vesting of the Assumed Performance Unit Award, the Unvested Equity Award CVR Consideration. Each Assumed Performance Unit Award will continue to have the same terms and conditions as applied to the corresponding Celgene PSU Award (other than performance-based vesting conditions) immediately prior to the effective time of the merger.

At the effective time of the merger, each Celgene RSA will be assumed by Bristol-Myers Squibb and converted into (i) an Assumed Restricted Stock Award that settles in a number of shares of Bristol-Myers Squibb common stock equal to the number of shares of Celgene common stock underlying the Celgene RSA immediately prior to the effective time of the merger multiplied by the Equity Award Exchange Ratio (rounded up to the nearest whole number of shares), and (ii) the right to receive, subject to the vesting of the Assumed Restricted Stock Award, the Unvested Equity Award CVR Consideration. Each Assumed Restricted Stock Award will continue to have the same terms and conditions as applied to the corresponding Celgene RSA immediately prior to the effective time of the merger.

The capitalized terms used within this section are subsequently defined in “The Merger Agreement—Treatment of Celgene Equity Awards” beginning on page 174 of this joint proxy statement/prospectus.

Recommendation of the Celgene Board of Directors (see page 105 )

The Celgene Board unanimously determined that the merger agreement and the transactions contemplated by the merger agreement (including the merger) are fair to and in the best interests of Celgene and its stockholders. The Celgene Board unanimously recommends that Celgene stockholders vote “FOR” the proposal to adopt the merger agreement. For the factors considered by the Celgene Board in reaching this decision, see “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Celgene’s Reasons for the Merger; Recommendation of the Celgene Board of Directors that Celgene Stockholders Adopt the Merger Agreement” beginning on page 105 of this joint proxy statement/prospectus.

The Celgene Board unanimously recommends that Celgene stockholders vote “FOR” the Celgene adjournment proposal. See “Celgene Proposal II: Adjournment of the Celgene Special Meeting” beginning on page 208 of this joint proxy statement/prospectus.

In addition, the Celgene Board unanimously recommends that Celgene stockholders vote “FOR” the Celgene compensation advisory proposal. See “Celgene Proposal III: Advisory Vote On Merger-Related Executive Compensation Arrangements” beginning on page 209 of this joint proxy statement/prospectus.

Recommendation of the Bristol-Myers Squibb Board of Directors (see page 109 )

The BMS Board determined that the merger agreement and the transactions contemplated by the merger agreement, including the merger and the stock issuance, are advisable, fair to and in the best interests of Bristol-Myers Squibb and its stockholders. The BMS Board unanimously recommends that Bristol-Myers Squibb stockholders vote “FOR” the stock issuance . For the factors considered by the BMS Board in reaching this decision, see “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Bristol-Myers Squibb’s Reasons for the Merger; Recommendation of the Bristol-Myers Squibb Board of Directors that Bristol-Myers Squibb Stockholders Approve the Stock Issuance” beginning on page 109 of this joint proxy statement/prospectus.

The BMS Board unanimously recommends that Bristol-Myers Squibb stockholders vote “FOR” the Bristol-Myers Squibb adjournment proposal. See “Bristol-Myers Squibb Proposal II: Adjournment of the Bristol-Myers Squibb Special Meeting” beginning on page 210 of this joint proxy statement/prospectus.

Opinions of Celgene’s Financial Advisors (see page 113 )

Opinion of J.P. Morgan Securities LLC

Celgene has engaged J.P. Morgan Securities LLC, which is referred to in this joint proxy statement/prospectus as J.P. Morgan, as a financial advisor in connection with the merger. On January 2, 2019, J.P. Morgan delivered to the Celgene Board its oral opinion, confirmed by delivery of a written opinion, dated January 2, 2019, to the effect that, as of such date and based on and subject to the assumptions made, procedures followed, matters considered and limitations and qualifications set forth in its written opinion, the merger consideration to be paid to the holders of Celgene common stock in the merger was fair, from a financial point of view, to such holders. See “Opinion of J.P. Morgan Securities LLC” beginning on page 113 of this joint proxy statement/prospectus.

The full text of J.P. Morgan’s written opinion, dated January 2, 2019, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken by J.P. Morgan in rendering its opinion, is attached to this joint proxy statement/prospectus as Annex C and is incorporated into this joint proxy statement/prospectus by reference in its entirety.

J.P. Morgan’s written opinion was addressed to the Celgene Board (in its capacity as such) in connection with and for the purposes of its evaluation of the merger, was directed only to the merger consideration to be paid to the holders of Celgene common stock in the merger and did not address any other aspect of the merger. The issuance of J.P. Morgan’s opinion was approved by a fairness committee of J.P. Morgan. The summary of the opinion of J.P. Morgan set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of such opinion. The opinion does not constitute a recommendation to any stockholder of Celgene as to how such stockholder should vote with respect to the merger or any other matter.

Opinion of Citigroup Global Markets Inc.

Celgene also has engaged Citigroup Global Markets Inc., which is referred to in this joint proxy statement/prospectus as Citigroup, as a financial advisor in connection with the merger. On January 2, 2019, Citigroup delivered to the Celgene Board its oral opinion, confirmed by delivery of a written opinion dated, January 2, 2019, to the effect that, as of such date and based on and subject to the assumptions made, procedures followed, matters considered and limitations and qualifications set forth in its written opinion, the merger consideration to be received by the holders of outstanding shares of Celgene common stock in the merger was fair, from a financial point of view, to such holders. See “Opinion of Citigroup Global Markets Inc.” beginning on page 123 of this joint proxy statement/prospectus.

The full text of Citigroup’s written opinion, dated January 2, 2019, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken by Citigroup in rendering its opinion, is attached to this joint proxy statement/prospectus as Annex D and is incorporated into this joint proxy statement/prospectus by reference in its entirety.

Citigroup’s opinion, the issuance of which was authorized by Citigroup’s fairness opinion committee, was provided to the Celgene Board (in its capacity as such) in connection with its evaluation of the merger and was limited to the fairness, from a financial point of view, as of the date of the opinion, to the holders of outstanding shares of Celgene common stock of the merger consideration to be received by such holders in the merger. Citigroup’s opinion does not address any other aspects or implications of the merger and does not constitute a recommendation to any stockholder as to how such stockholder should vote or act on any matters relating to the merger or otherwise. Citigroup’s opinion does not address the underlying business decision of Celgene to effect the merger, the relative merits of the merger as compared to any alternative business strategies that might exist for Celgene or the effect of any other transaction in which Celgene might engage.

Opinions of Bristol-Myers Squibb’s Financial Advisors (see page 132 )

Opinion of Morgan Stanley

On January 2, 2019, Morgan Stanley & Co. LLC, which is referred to in this joint proxy statement/prospectus as Morgan Stanley, rendered its oral opinion, which was subsequently confirmed by delivery of a written opinion, to the BMS Board to the effect that as of such date, and based upon and subject to the various assumptions made,

procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Morgan Stanley as set forth in its written opinion, the merger consideration to be paid by Bristol-Myers Squibb pursuant to the merger agreement was fair from a financial point of view to Bristol-Myers Squibb.

The full text of Morgan Stanley’s written opinion to the BMS Board , dated January 2, 2019, is attached to this joint proxy statement/prospectus as Annex E, and is incorporated by reference in this joint proxy statement/prospectus in its entirety. Bristol-Myers Squibb stockholders should read the opinion in its entirety for a discussion of the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of review undertaken by Morgan Stanley in rendering its opinion. This summary is qualified in its entirety by reference to the full text of such opinion. Morgan Stanley’s opinion was directed to the BMS Board and addressed only the fairness from a financial point of view to Bristol-Myers Squibb, as of the date of the opinion, of the merger consideration to be paid by Bristol-Myers Squibb pursuant to the merger agreement. Morgan Stanley’s opinion did not address any other aspects of the merger and did not and does not constitute a recommendation as to how stockholders of Bristol-Myers Squibb or Celgene should vote at the stockholders’ meetings to be held in connection with the merger.

Opinion of Dyal Co.

On January 2, 2019, Dyal Co. LLC, which is referred to in this joint proxy statement/prospectus as Dyal Co., rendered its oral opinion, which was subsequently confirmed by delivery of a written opinion, to the BMS Board to the effect that as of such date, and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Dyal Co. as set forth in its written opinion, the merger consideration to be paid by Bristol-Myers Squibb pursuant to the merger agreement was fair from a financial point of view to Bristol-Myers Squibb.

The full text of Dyal Co.’s written opinion to the BMS Board , dated January 2, 2019, is attached to this joint proxy statement/prospectus as Annex F, and is incorporated by reference in this joint proxy statement/prospectus in its entirety. Bristol-Myers Squibb stockholders should read the opinion in its entirety for a discussion of the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of review undertaken by Dyal Co. in rendering its opinion. This summary is qualified in its entirety by reference to the full text of such opinion. Dyal Co.’s opinion was directed to the BMS Board and addressed only the fairness from a financial point of view to Bristol-Myers Squibb, as of the date of the opinion, of the merger consideration to be paid by Bristol-Myers Squibb pursuant to the merger agreement. Dyal Co.’s opinion did not address any other aspects of the merger and did not and does not constitute a recommendation as to how stockholders of Bristol-Myers Squibb or Celgene should vote at the stockholders’ meetings to be held in connection with the merger.

Opinion of Evercore

On January 2, 2019, Evercore Group L.L.C., which is referred to in this joint proxy statement/prospectus as Evercore, rendered its oral opinion, which was subsequently confirmed by delivery of a written opinion, to the BMS Board to the effect that as of such date, and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Evercore as set forth in its written opinion, the merger consideration to be paid by Bristol-Myers Squibb pursuant to the merger agreement was fair from a financial point of view to Bristol-Myers Squibb.

The full text of Evercore’s written opinion to the BMS Board , dated January 2, 2019, is attached to this joint proxy statement/prospectus as Annex G, and is incorporated by reference in this joint proxy statement/prospectus in its entirety. Bristol-Myers Squibb stockholders should read the opinion in its entirety for a discussion of the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of review undertaken by Evercore in rendering its opinion. This summary is qualified in its entirety by reference to the full text of such opinion. Evercore’s opinion was directed to the BMS Board and addressed only the fairness from a financial point of view to Bristol-Myers Squibb, as of the date of the opinion, of the merger consideration to be paid by

Bristol-Myers Squibb pursuant to the merger agreement. Evercore’s opinion did not address any other aspects of the merger and did not and does not constitute a recommendation as to how stockholders of Bristol-Myers Squibb or Celgene should vote at the stockholders’ meetings to be held in connection with the merger.

Ownership of Bristol-Myers Squibb Common Stock After the Merger (see page 93 )

Based on the number of shares of Celgene common stock outstanding as of January 29, 2019, Bristol-Myers Squibb expects to issue approximately 701,024,507 shares of Bristol-Myers Squibb common stock to Celgene stockholders pursuant to the merger. The actual number of shares of Bristol-Myers Squibb common stock to be issued pursuant to the merger will be determined at completion of the merger based on the number of shares of Celgene common stock outstanding at such time. In addition, shares of Bristol-Myers Squibb common stock may be issued from time to time following the effective time of the merger to holders of Celgene equity awards on the terms set forth in the merger agreement. See “The Merger Agreement—Treatment of Celgene Equity Awards” beginning on page 174 of this joint proxy statement/prospectus for a more detailed explanation. Based on the number of shares of Celgene common stock outstanding as of January 29, 2019, and the number of shares of Bristol-Myers Squibb common stock outstanding as of January 24, 2019, it is expected that, immediately after completion of the merger, former Celgene stockholders will own approximately 31% of the oustanding shares of Bristol-Myers Squibb common stock.

Governance Matters Following Completion of the Merger (see page 176 )

Upon completion of the merger, it is expected that the BMS Board will be composed of 13 members. In addition to the individuals serving on the BMS Board at the effective time of the merger, Bristol-Myers Squibb is required to take all necessary corporate action so that, effective at the completion of the merger, the number of members of the BMS Board will be expanded to include two additional members, jointly designated by Celgene and Bristol-Myers Squibb, who are serving as directors of Celgene immediately prior to the completion of the merger. As of the date of this joint proxy statement/prospectus, no determination has been made as to the identity of the two Celgene designees who will be appointed to the BMS Board. See “The Merger Agreement—Governance Matters Following Completion of the Merger” beginning on page 176 for further information.

Interests of Celgene’s Directors and Executive Officers in the Merger (see page 202 )

In considering the recommendation of the Celgene Board to adopt the merger agreement, Celgene stockholders should be aware that Celgene’s directors and executive officers have interests in the merger that may be different from, or in addition to, the interests of Celgene stockholders generally, including potential severance benefits, treatment of outstanding Celgene equity awards pursuant to the merger agreement and potential vesting of such awards in connection with a qualifying termination of employment on or following the merger (or, in certain circumstances, a termination of employment that otherwise occurs in connection with the merger), and rights to ongoing indemnification and insurance coverage. The Celgene Board was aware of these interests and considered them, among other matters, in evaluating and negotiating the merger agreement, in reaching its decision to approve the merger agreement and the transactions contemplated by the merger agreement (including the merger), and in recommending to Celgene stockholders that the merger agreement be adopted.

These interests are described in further detail under “Interests of Celgene’s Directors and Executive Officers in the Merger” and “The Merger Agreement—Indemnification and Insurance” beginning on pages 202 and 195, respectively, of this joint proxy statement/prospectus.

Listing of Bristol-Myers Squibb Common Stock and CVRs; Delisting and Deregistration of Shares of Celgene Common Stock (see page 176 )

The merger agreement obligates Bristol-Myers Squibb to use its reasonable best efforts to cause the Bristol-Myers Squibb common stock and the CVRs to be issued in the merger to be listed on the NYSE, subject to official notice of issuance, prior to the completion of the merger. See “The Merger Agreement—Listing of Bristol-Myers Squibb Common Stock and the CVRs” beginning on page 176 for further information. Approval for listing on the NYSE of the Bristol-Myers Squibb common stock and the CVRs, subject to official notice of issuance, is a condition to the obligations of Celgene and Bristol-Myers Squibb to complete the merger as

described under “The Merger Agreement—Conditions to Completion of the Merger” beginning on page 176 of this joint proxy statement/prospectus. If the merger is completed, shares of Celgene common stock will no longer be listed on Nasdaq and will be deregistered under the Exchange Act.

Appraisal or Dissenters’ Rights Available to Celgene Stockholders (see page 159 )

If the merger is completed, Celgene stockholders who do not vote in favor of the adoption of the merger agreement and who otherwise comply with the applicable provisions of Section 262 of the DGCL will be entitled to exercise appraisal rights thereunder and obtain payment in cash for the fair value of their shares of Celgene, subject to certain limitations under the DGCL. Any shares of Celgene common stock held by a Celgene stockholder on the date of making an appraisal demand, who continues to own such shares through the effective date of the merger, who has not voted in favor of the adoption of the merger agreement and who has demanded appraisal for such shares in accordance with the DGCL will have the right to obtain payment in cash for the fair value of their shares of Celgene in lieu of the merger consideration, unless such Celgene stockholder fails to perfect, effectively withdraws, waives or otherwise loses such stockholder’s appraisal rights under the DGCL. If, after the completion of the merger, such holder of Celgene common stock fails to perfect, effectively withdraws, waives or otherwise loses his, her or its appraisal rights, each such share will be treated as if it had been converted as of the completion of the merger into a right to receive the merger consideration.

Due to the complexity of the procedures for exercising your appraisal rights, Celgene stockholders who are considering exercising such rights are encouraged to seek the advice of legal counsel. Failure to strictly comply with these provisions will result in the loss of appraisal rights. See the section titled “Appraisal or Dissenters’ Rights for Celgene Stockholders” contained in this joint proxy statement/prospectus for additional information and the text of Section 262 of the DGCL, which you are encouraged to read carefully and in their entirety.

Completion of the Merger Is Subject to Certain Conditions (see page 176 )

As more fully described in this joint proxy statement/prospectus and in the merger agreement, the obligation of each of Bristol-Myers Squibb and Merger Sub, on the one hand, and Celgene, on the other hand, to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of a number of conditions.

Mutual Conditions to Completion . The obligation of each of Celgene, Bristol-Myers Squibb and Merger Sub to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of the following conditions:

Additional Conditions to Completion for the Benefit of Bristol-Myers Squibb and Merger Sub. In addition, the obligation of Bristol-Myers Squibb and Merger Sub to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of the following conditions:

Additional Conditions to Completion for the Benefit of Celgene. In addition, the obligation of Celgene to complete the merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver) of the following conditions:

Neither Bristol-Myers Squibb nor Celgene can be certain when, or if, the conditions to the merger will be satisfied or waived, or that the merger will be completed.

The Merger May Not Be Completed Without the Required Regulatory Approvals (see page 30 )

Completion of the merger is conditioned upon the expiration or early termination of the waiting period relating to the merger under the HSR Act and the receipt of approvals under the antitrust laws of certain specified foreign jurisdictions.

Under the HSR Act, certain transactions, including the merger, may not be completed unless certain waiting period requirements have expired or been terminated. The HSR Act provides that each party must file a pre-merger notification with the Federal Trade Commission, which is referred to in this joint proxy statement/prospectus as the FTC, and the Antitrust Division of the U.S. Department of Justice, which is referred to in this joint proxy statement/prospectus as the DOJ. A transaction notifiable under the HSR Act may not be completed until the expiration of a 30-calendar-day waiting period following the parties’ filings of their respective HSR Act notification forms or the early termination of that waiting period. The parties may also choose to voluntarily re-start the initial 30-day waiting period by following certain prescribed procedures. After the expiration of the initial waiting period (or the re-started initial waiting period), the DOJ or the FTC may issue a Request for Additional Information and Documentary Material, which is referred to in this joint proxy statement/prospectus as a Second Request. If a Second Request is issued, the parties may not complete the merger until they substantially comply with the Second Request and observe a second 30-calendar-day waiting period, unless the waiting period is terminated earlier.

Each of Bristol-Myers Squibb and Celgene filed its respective HSR Act notification and report with respect to the merger on January 16, 2019.

In addition, the European Commission and certain other non-U.S. governmental authorities must approve, or be notified of, the merger, and Bristol-Myers Squibb and/or Celgene and/or their respective subsidiaries will file all such statements, notices or applications, as are required by the laws of applicable non-U.S. governmental authorities.

Neither Bristol-Myers Squibb nor Celgene is aware of any material governmental approvals or actions that are required for completion of the merger other than those described above. It is presently contemplated that if any such additional material governmental approvals or actions are required, those approvals or actions will be sought.

Bristol-Myers Squibb and Celgene have agreed to use their respective reasonable best efforts to take, or cause to be taken, all actions and to do, or cause to be done, all things necessary, proper or advisable to consummate the merger, including (i) preparing and filing as promptly as practicable all necessary regulatory filings, (ii) supplying information that may be requested by regulatory authorities pursuant to applicable laws, and (iii) cooperating with the other parties, to the extent reasonable, in their efforts to comply with their obligations under the merger agreement. Bristol-Myers Squibb and Celgene are also required to use their reasonable best efforts to contest any governmental action challenging the legality of the merger or any order prohibiting the parties from completing the merger.

Bristol-Myers Squibb’s obligation to use reasonable best efforts (as described in the preceding paragraph) also includes taking and agreeing to take all actions and doing or agreeing to do all things necessary, proper or advisable under the relevant law (including divestitures, hold separate arrangements, the termination, assignment, novation or modification of contracts or other business relationships, the acceptance of restrictions on business operations and the entry into other commitments and limitations). However, Bristol-Myers Squibb is not required to take any action or agree to any term or condition if doing so would have or would reasonably be expected to have, individually or in the aggregate, a material adverse effect on the financial condition, business or results of operations of Bristol-Myers Squibb, Celgene and their respective subsidiaries, taken as a whole, after giving effect to the completion of the merger. In addition, in connection with obtaining the regulatory approvals required to complete the merger, (i) neither Bristol-Myers Squibb nor Celgene is required to take any action or agree to any term or condition that is not conditioned upon completion of the merger and (ii) Celgene is not permitted to take any action or agree to any term or condition without Bristol-Myers Squibb’s consent, but if requested by Bristol-Myers Squibb, Celgene is required to take any such action to obtain regulatory approvals required to complete the merger subject to the immediately preceding clause (i). See “The Merger Agreement—Conditions to Completion of the Merger” beginning on page 176 .

Description of Debt Financing (see page 168 )

Bristol-Myers Squibb’s obligation to complete the transaction is not contingent on the receipt by Bristol-Myers Squibb of any financing. Bristol-Myers Squibb estimates that it will need approximately $36 billion in order to pay Celgene stockholders the cash amounts due to them as merger consideration under the merger agreement and to pay related fees and transaction costs in connection with the transaction. Bristol-Myers Squibb anticipates that the funds needed to pay the foregoing amount will be derived from (i) cash on hand, (ii) borrowings under its existing and new credit facilities described below, (iii) the proceeds from the sale of debt securities or (iv) any combination of the foregoing. In addition, either prior to or after the closing of the transaction, Bristol-Myers Squibb may conduct one or more exchange offers, offers to purchase and/or consent solicitations with respect to Celgene’s outstanding debt securities. The terms and timing of any such debt offerings, exchange offers, offers to purchase and/or consent solicitations has not been determined as of the date of this joint proxy statement/prospectus. This joint proxy statement/prospectus does not constitute an offer to sell or the solicitation of an offer to buy any debt securities of Bristol-Myers Squibb or Celgene. It does not constitute a prospectus or prospectus equivalent document for any such securities. No offering of any debt securities of Bristol-Myers Squibb shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act or an exemption therefrom.

In connection with entry into the merger agreement, on January 2, 2019, Bristol-Myers Squibb entered into a bridge facility commitment letter, which is referred to in this joint proxy statement/prospectus as the bridge facility commitment letter, and the credit facility (if any) established in accordance with the terms thereof is referred to in this joint proxy statement/prospectus as the bridge facility, with Morgan Stanley Senior Funding, Inc. and MUFG Bank, Ltd., which are referred to in this joint proxy statement/prospectus as MSSF and MUFG, respectively, to finance up to $33.5 billion of the (i) cash consideration in connection with the merger, (ii) repayment of certain existing indebtedness of Celgene (if applicable) and (iii) fees and expenses in connection with the foregoing, to the extent that Bristol-Myers Squibb has not received $33.5 billion of net cash proceeds from a combination of (A) cash on the balance sheet, (B) the issuance by Bristol-Myers Squibb of unsecured debt securities, equity securities and/or equity-linked securities in public or private offerings the proceeds of which are to be used to finance the merger, and (C) the incurrence by Bristol-Myers Squibb of unsecured term loan facilities, in each case, at or prior to completion of the merger. MSSF and MUFG each provided a commitment to fund loans under the bridge facility and are collectively referred to in this joint proxy statement/prospectus as the initial bridge commitment parties. On January 18, 2019, Bristol-Myers Squibb and

the initial bridge commitment parties entered into a joinder agreement to the bridge facility commitment letter, which is referred to in this joint proxy statement/prospectus as the bridge joinder agreement, with certain additional commitment parties, which are collectively referred to in this joint proxy statement/prospectus as the additional bridge commitment parties. The bridge joinder agreement amends the bridge facility commitment letter and reallocates the commitments of the initial bridge commitment parties to fund loans under the bridge facility among the initial bridge commitment parties and the additional bridge commitment parties. The initial bridge commitment parties together with the additional bridge commitment parties are collectively referred to in this joint proxy statement/prospectus as the bridge commitment parties. The bridge commitment parties’ obligation to fund the bridge facility is subject to several limited conditions as set forth in the bridge facility commitment letter, including, among others, completion of the merger, the non-occurrence of a material adverse effect (as defined in the bridge facility commitment letter) on Celgene, the accuracy in all material respects of certain representations and warranties related to Bristol-Myers Squibb (including the absence of certain events of default by Bristol-Myers Squibb), the delivery of certain financial statements of Bristol-Myers Squibb and Celgene and other customary conditions to completion.

In connection with the merger, on January 18, 2019, Bristol-Myers Squibb entered into a term loan agreement, which is referred to in this joint proxy statement/prospectus as the term loan agreement, with a group of banks and other financial institutions named therein, which are collectively referred to in this joint proxy statement/prospectus as the term lenders, consisting of a $1 billion 364-day tranche, a $4 billion three-year tranche and a $3 billion five-year tranche, which is referred to in this joint proxy statement/prospectus as the term loan facility and the loans thereunder are referred to as the term loans, to finance $8 billion of (i) cash consideration in connection with the merger, (ii) the repayment of certain existing indebtedness of Celgene (if applicable) and (iii) fees and expenses in connection with the foregoing. The occurrence of the effective date under the term loan agreement on January 18, 2019 had the effect of reducing the commitments under the bridge facility by a principal amount of $8 billion to $25.5 billion. The term lenders’ obligation to fund the term loan facility is subject to several limited conditions as set forth in the term loan agreement, including, among others, completion of the merger, the non-occurrence of a material adverse effect (as defined in the term loan agreement) on Celgene, the accuracy in all material respects of certain representations and warranties related to Bristol-Myers Squibb (including the absence of certain events of default by Bristol-Myers Squibb), the delivery of certain financial statements of Bristol-Myers Squibb and Celgene and other customary conditions to completion.

On January 25, 2019, Bristol-Myers Squibb entered into a 364-day revolving loan agreement, which is referred to in this joint proxy statement/prospectus as the 364-day revolving loan agreement, with a group of banks and other financial institutions named therein, which are collectively referred to in this joint proxy statement/prospectus as the 364-day revolving lenders, consisting of a $2 billion 364-day tranche. The 364-day revolving loan agreement replaces in full Bristol-Myers Squibb’s existing 364-day revolving facility and shall be used for general corporate purposes, which is referred to in this joint proxy statement/prospectus as the 364-day revolving loan facility and the loans thereunder are referred to as the 364-day revolving loans. The 364-day revolving loan facility is available to be drawn in full, subject to customary conditions to borrowing.

On January 25, 2019, Bristol-Myers Squibb also entered into a three-year revolving loan agreement, which is referred to in this joint proxy statement/prospectus as the three-year revolving loan agreement, with a group of banks and other financial institutions named therein, which are collectively referred to in this joint proxy statement/prospectus as the three-year revolving lenders, consisting of a $1 billion three-year tranche that shall be used for general corporate purposes, which is referred to in this joint proxy statement/prospectus as the three-year revolving loan facility and the loans thereunder are referred to as the three-year revolving loans. The three-year revolving loan facility is available to be drawn in full, subject to customary conditions to borrowing.

Bristol-Myers Squibb and Celgene Expect the Merger to be Completed in the Third Quarter of 2019 (see page 32 )

The merger is required to be completed three business days after the conditions to its completion have been satisfied or, to the extent permitted by applicable law, waived, unless otherwise mutually agreed by the parties. As of the date of this joint proxy statement/prospectus, Bristol-Myers Squibb and Celgene expect the merger to be completed in the third quarter of 2019. However, there can be no assurance as to when, or if, the merger will be completed.

No Solicitation by Celgene or Bristol-Myers Squibb (see page 185 )

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions set forth in the merger agreement, each of Celgene and Bristol-Myers Squibb has agreed not to, and to cause its subsidiaries and its subsidiaries’ directors and officers not to, and to use its reasonable best efforts to cause its and its subsidiaries’ other employees and agents, investment bankers, attorneys, accountants, consultants, advisors and representatives, which are collectively referred to in this joint proxy statement/prospectus as representatives, not to, directly or indirectly, (i) solicit, initiate or take any action to knowingly facilitate or knowingly encourage (including by way of furnishing information) the submission of any acquisition proposal (as defined in “The Merger Agreement—No Solicitation,” beginning on page 185 of this joint proxy statement/prospectus), (ii) enter into or participate in any discussions or negotiations with, furnish any information relating to that party or any of its subsidiaries or afford access to the business, properties, assets, books or records of that party or any of its subsidiaries to, otherwise cooperate in any way with, or knowingly assist, participate in, knowingly facilitate or knowingly encourage any effort by, any third party that such party knows is seeking to make, or has made, an acquisition proposal, (iii) (A) withdraw or qualify, amend or modify in any manner adverse to the other party (or fail to include in this joint proxy statement/prospectus) the recommendation of that party’s board of directors that such party’s stockholders vote in favor of the adoption of the merger agreement or such party’s stockholders vote in favor of the approval of the stock issuance, as applicable, or (B) recommend, adopt or approve or publicly propose to recommend, adopt or approve any acquisition proposal (any of the actions described in this clause (iii) are referred to in this joint proxy statement/prospectus as an adverse recommendation change) or (iv) take any action to make any “moratorium,” “control share acquisition,” “fair price,” “supermajority,” “affiliate transactions” or “business combination statute or regulation” or other similar antitakeover laws and regulations of the State of Delaware, including Section 203 of the DGCL, inapplicable to any third party or any acquisition proposal.

However, if at any time prior to the adoption of the merger agreement by Celgene stockholders, in the case of Celgene, or at any time prior to the approval of the stock issuance by Bristol-Myers Squibb stockholders, in the case of Bristol-Myers Squibb, Celgene or Bristol-Myers Squibb, as applicable, receives a bona fide written acquisition proposal made after the date of the merger agreement which has not resulted from a violation of the solicitation restrictions described in “The Merger Agreement—No Solicitation,” beginning on page 185 of this joint proxy statement/prospectus, the board of directors of that party is permitted to, directly or indirectly through its representatives, and subject to certain exceptions and qualifications described in the merger agreement:

superior proposal, but in the case of this clause (iii) only if the Celgene Board or the BMS Board, as applicable, determines in good faith, after consultation with its financial advisor and outside legal counsel, that the failure to take such action would be reasonably likely to be inconsistent with its fiduciary duties under applicable law.

For more information on the solicitation restrictions binding on Celgene and Bristol-Myers Squibb, see “The Merger Agreement—No Solicitation” beginning on page 185 of this joint proxy statement/prospectus.

Termination of the Merger Agreement (see page 197 )

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions set forth in the merger agreement, the merger agreement may be terminated at any time before completion of the merger in any of the following ways:

Termination Fees and Expenses (see page 199 )

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions set forth in the merger agreement, Celgene has agreed to pay the Celgene termination fee, if the merger agreement is terminated under any of the following circumstances:

If the merger agreement is terminated by either Bristol-Myers Squibb or Celgene as a result of the Celgene stockholders voting on and failing to adopt the merger agreement at the Celgene special meeting or at any

adjournment or postponement thereof, then Celgene will pay Bristol-Myers Squibb the Bristol-Myers Squibb fee reimbursement. If the Celgene termination fee is payable by Celgene after the time Celgene pays the Bristol-Myers Squibb fee reimbursement, the amount of the Celgene termination fee will be reduced by the Bristol-Myers Squibb fee reimbursement.

As more fully described in this joint proxy statement/prospectus and in the merger agreement, and subject to the terms and conditions set forth in the merger agreement, Bristol-Myers Squibb has agreed to pay the Bristol-Myers Squibb termination fee, if the merger agreement is terminated under any of the following circumstances:

If the merger agreement is terminated by either Bristol-Myers Squibb or Celgene as a result of the Bristol-Myers Squibb stockholders voting on and failing to approve the stock issuance at the Bristol-Myers Squibb special meeting or at any adjournment or postponement thereof, then Bristol-Myers Squibb will pay Celgene the Celgene fee reimbursement. If the Bristol-Myers Squibb termination fee is payable by Bristol-Myers Squibb after the time Bristol-Myers Squibb pays the Celgene fee reimbursement, the amount of the Bristol-Myers Squibb termination fee will be reduced by the Celgene fee reimbursement.

Except in the case of fraud or willful breach of any covenant or agreement in the merger agreement, if either party receives the applicable termination fee in accordance with the provisions of the merger agreement, the receipt of such termination fee will be the receiving party’s sole and exclusive remedy against the paying party.

See “The Merger Agreement—Termination Fees and Expenses” beginning on page 199 of this joint proxy statement/prospectus for a more complete description of the circumstances under which Celgene or Bristol-Myers Squibb will be required to pay a termination fee or expense reimbursement.

Specific Performance; Remedies (see page 201 )

Under the merger agreement, each of Bristol-Myers Squibb and Celgene is entitled to an injunction or injunctions to prevent breaches or threatened breaches of the merger agreement and to specifically enforce the terms and provisions of the merger agreement.

Material U.S. Federal Income Tax Consequences (see page 164 )

The exchange of shares of Celgene common stock for the merger consideration pursuant to the merger will be a taxable transaction for U.S. federal income tax purposes. Accordingly, a Celgene stockholder that is a U.S. holder (as defined in “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences”) will recognize taxable capital gain or loss in an amount equal to the difference, if any, between (i) the sum of (A) the amount of cash, including cash in lieu of fractional shares, received by such U.S. holder in the merger, (B) the fair market value of the shares of Bristol-Myers Squibb common stock received by such U.S. holder in the merger, and (C) the fair market value of the CVRs received by such U.S. holder in the merger, each determined on the date of the completion of the merger and (ii) such U.S. holder’s adjusted tax basis in the shares of Celgene common stock exchanged therefor. With respect to a Celgene stockholder that is a non-U.S. holder (as defined in “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences”), the exchange of shares of Celgene common stock for the merger consideration pursuant to the merger generally will not result in tax to such non-U.S. holder under U.S. federal income tax laws unless such non-U.S. holder has certain connections with the United States.

Each Celgene stockholder is urged to read the discussion in the section entitled “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences” beginning on page 164 of this joint proxy statement/prospectus and to consult its tax advisor to determine the particular U.S. federal, state or local or non-U.S. income or other tax consequences to it of the merger.

Accounting Treatment (see page 167 )

The merger will be accounted for as an acquisition of a business. Bristol-Myers Squibb will record assets acquired and liabilities assumed from Celgene primarily at their respective fair values at the date of completion of the merger. Any excess of the purchase price (as described under Note 5. Estimate of consideration expected to be transferred in the Celgene merger and preliminary purchase price allocation under “Certain Unaudited Pro Forma Condensed Combined Financial Statements” beginning on page 58 of this joint proxy statement/prospectus) over the net fair value of such assets and liabilities will be recorded as goodwill.

Rights of Celgene Stockholders Will Change as a Result of the Merger (see page 225 )

Celgene stockholders will have different rights once they become Bristol-Myers Squibb stockholders due to differences between the organizational documents of Bristol-Myers Squibb and Celgene. These differences are described in more detail under “Comparison of Stockholder Rights” beginning on page 225 of this joint proxy statement/prospectus.

Litigation Relating to the Merger (see page 170 )

As of January 30, 2019, no complaints had been filed by purported Celgene stockholders challenging the merger, and no complaints had been filed by purported Bristol-Myers Squibb stockholders challenging the merger.

Risk Factors (see page 38 )

You should also carefully consider the risks that are described in the section entitled “Risk Factors” beginning on page 38 of this joint proxy statement/prospectus.

common stock they receive as a result of the merger. Other Celgene stockholders, such as funds with limitations on their permitted holdings of stock in individual issuers, may be required to sell the shares of Bristol-Myers Squibb common stock they receive as a result of the merger. Any such sales of Bristol-Myers Squibb common stock could have the effect of depressing the market price for Bristol-Myers Squibb common stock.

In addition, in the future Bristol-Myers Squibb may issue additional securities to raise capital. Bristol-Myers Squibb may also acquire interests in other companies by issuing Bristol-Myers Squibb common stock to finance the acquisition, in whole or in part. Bristol-Myers Squibb may also issue securities convertible into Bristol-Myers Squibb common stock.

Moreover, general fluctuations in stock markets could have a material adverse effect on the market for, or liquidity of, the Bristol-Myers Squibb common stock, regardless of Bristol-Myers Squibb’s actual operating performance.

The businesses of Bristol-Myers Squibb differ from those of Celgene in important respects and, accordingly, the results of operations of the combined company after the merger, as well as the market price of shares of Bristol-Myers Squibb common stock, may be affected by factors different from those that are currently affecting, historically have affected or would in the future affect the results of operations of Celgene and Bristol-Myers Squibb as stand-alone public companies, as well as the market price of shares of Celgene common stock and Bristol-Myers Squibb common stock prior to completion of the merger. For further information on the respective businesses of Bristol-Myers Squibb and Celgene and certain factors to consider in connection with those businesses, see the documents incorporated by reference into this joint proxy statement/prospectus and referred to under “Where You Can Find More Information” beginning on page 250 of this joint proxy statement/prospectus.

Bristol-Myers Squibb and Celgene may have difficulty attracting, motivating and retaining executives and other key employees in light of the merger.

Bristol-Myers Squibb’s success after the transaction will depend in part on the ability of Bristol-Myers Squibb to retain key executives and other employees of Celgene. Uncertainty about the effect of the merger on Bristol-Myers Squibb and Celgene employees may have an adverse effect on each of Bristol-Myers Squibb and Celgene separately and consequently the combined business. This uncertainty may impair Bristol-Myers Squibb’s and/or Celgene’s ability to attract, retain and motivate key personnel. Employee retention may be particularly challenging during the pendency of the merger, as employees of Bristol-Myers Squibb and Celgene may experience uncertainty about their future roles in the combined business.

Additionally, Celgene’s officers and employees may hold shares of Celgene common stock, and, if the merger is completed, these officers and employees may be entitled to the merger consideration in respect of such shares of Celgene common stock. Officers and employees may hold Celgene Stock Options, Celgene RSUs and Celgene PSUs that are subject to accelerated vesting upon a termination without cause and, in some cases, a resignation for “good reason” on or following, completion of the merger. Pursuant to severance plans maintained by Celgene, certain key employees of Celgene are also entitled to receive severance payments upon a termination without cause and/or a resignation for “good reason” on or following completion of the merger. Under these plans, certain key employees of Celgene potentially could resign from his or her employment following specified circumstances set forth in the applicable plan, including an adverse change in his or her title, authority or responsibilities, compensation and benefits or primary office location that would result in the payments under the arrangements. These payments, individually or in the aggregate, could make retention of Celgene officers and employees more difficult.

Furthermore, if key employees of Bristol-Myers Squibb or Celgene depart or are at risk of departing, including because of issues relating to the uncertainty and difficulty of integration, financial security or a desire not to become employees of the combined business, Bristol-Myers Squibb may have to incur significant costs in retaining such individuals or in identifying, hiring and retaining replacements for departing employees and may lose significant expertise and talent, and the combined company’s ability to realize the anticipated benefits of the merger may be materially and adversely affected. No assurance can be given that the combined company will be able to attract or retain key employees to the same extent that Celgene has been able to attract or retain employees in the past.

In order to complete the merger, Bristol-Myers Squibb and Celgene must obtain certain governmental approvals, and if such approvals are not granted or are granted with conditions that become applicable to the parties, completion of the merger may be jeopardized or prevented or the anticipated benefits of the merger could be reduced.

Completion of the merger is conditioned upon the expiration or early termination of the waiting period relating to the merger under the HSR Act and the receipt of approvals under the antitrust laws of certain specified foreign jurisdictions. Although Bristol-Myers Squibb and Celgene have agreed in the merger agreement to use their reasonable best efforts, subject to certain limitations, to make certain governmental filings and obtain the required governmental approvals, as the case may be, there can be no assurance that the relevant waiting periods will expire or terminate or the required approvals will be obtained and no assurance that the merger will be completed.

In addition, the governmental authorities from which these approvals are required have broad discretion in administering the governing laws and regulations, and may take into account various facts and circumstances in their consideration of the merger, including other potential transactions in the biopharmaceutical industry or other industries. These governmental authorities may be affected by government shutdowns, which could result in delays regarding any potential approvals or other actions. These governmental authorities may initiate proceedings seeking to prevent, or otherwise seek to prevent, the merger. As a condition to the approval of the merger or related transactions, these governmental authorities also may impose requirements, limitations or costs, require divestitures or place restrictions on the conduct of Bristol-Myers Squibb’s business or Celgene’s business after completion of the merger. Under the terms of the merger agreement, Bristol-Myers Squibb is obligated to use its reasonable best efforts to complete the merger, but is not required to take any actions or agree to any terms or conditions in connection with obtaining any regulatory approvals for completing the merger that would have, or would reasonably be expected to have, individually or in the aggregate, a material adverse effect on the financial condition, business or results of operations of Bristol-Myers Squibb, Celgene and their respective subsidiaries, taken as a whole, after giving effect to the completion of the merger. Celgene has also agreed, if requested in writing by Bristol-Myers Squibb, to take any such actions to obtain any governmental approval that is a condition for completing the merger, see “The Merger Agreement—Reasonable Best Efforts Covenant” beginning on page 188 of this joint proxy statement/prospectus for additional information related to these provisions.

However, notwithstanding the provisions of the merger agreement, either Bristol-Myers Squibb or Celgene could become subject to terms or conditions in connection with the expiration or termination of such waiting periods or the receipt of other required approvals the imposition of which could adversely affect Bristol-Myers Squibb’s ability to integrate Celgene’s operations with Bristol-Myers Squibb’s operations, reduce the anticipated benefits of the merger or otherwise materially and adversely affect the combined company’s business and results of operations after completion of the merger. See “The Merger Agreement—Conditions to Completion of the Merger” and “The Merger Agreement—Reasonable Best Efforts Covenant” beginning on pages 176 and 188, respectively, of this joint proxy statement/prospectus.

In addition to receipt of certain governmental approvals, completion of the merger is subject to a number of other conditions, and if these conditions are not satisfied or waived, the merger will not be completed.

The obligations of Bristol-Myers Squibb and Celgene to complete the merger are subject to satisfaction or waiver of a number of conditions in addition to receipt of certain specified governmental approvals, including, among other conditions: (i) adoption of the merger agreement by Celgene stockholders at the Celgene special meeting; (ii) approval of the stock issuance by Bristol-Myers Squibb stockholders at the Bristol-Myers Squibb special meeting; (iii) approval for the listing on the NYSE of the shares of Bristol-Myers Squibb common stock and CVRs to be issued in the merger; (iv) absence of any injunction or order that prohibits completion of the transaction; (v) accuracy of the representations and warranties made in the merger agreement by the other party, subject to the applicable materiality standards set forth in the merger agreement; (vi) performance in all material respects by the other party of the covenants and agreements required to be performed by such party at or prior to completion of the merger; and (vii) the effectiveness of the registration statement on Form S-4 relating to the merger and no stop order suspending the effectiveness of the registration statement and no proceedings for such purpose are pending before the SEC. For a more complete summary of the conditions that must be satisfied or

waived prior to completion of the merger, see “The Merger Agreement—Conditions to Completion of the Merger” beginning on page 176 of this joint proxy statement/prospectus. There can be no assurance that the conditions to completion of the merger will be satisfied or waived or that the merger will be completed within the expected time frame, or at all.

In addition, the Bristol-Myers Squibb special meeting and the Celgene special meeting may take place before certain governmental approvals have been obtained and, therefore, before the terms on which such governmental approvals may be obtained, or the conditions to obtaining such governmental approvals that may be imposed, are known. As a result, if Bristol-Myers Squibb stockholders approve the stock issuance at the Bristol-Myers Squibb special meeting, or Celgene stockholders adopt the merger agreement at the Celgene special meeting, Bristol-Myers Squibb and Celgene may make decisions after the respective meetings to waive a condition as to the receipt of certain specified governmental approvals or to take certain actions required to obtain such governmental approvals without seeking further stockholder approval, and such actions could have an adverse effect on the combined company.

Failure to complete the merger could negatively impact the stock price and the future business and financial results of Bristol-Myers Squibb and Celgene.

If the merger is not completed for any reason, including as a result of Celgene stockholders failing to adopt the merger agreement or Bristol-Myers Squibb stockholders failing to approve the stock issuance, the ongoing businesses of Bristol-Myers Squibb and Celgene may be materially and adversely affected and, without realizing any of the benefits of having completed the merger, Bristol-Myers Squibb and Celgene would be subject to a number of risks, including the following:

In addition, each of Bristol-Myers Squibb and Celgene could be subject to litigation related to any failure to complete the merger or related to any proceeding to specifically enforce Bristol-Myers Squibb’s or Celgene’s obligation to perform their respective obligations under the merger agreement.

If any of these risks materialize, they may materially and adversely affect Bristol-Myers Squibb’s and/or Celgene’s businesses, financial condition, financial results, ratings, stock prices and/or bond prices.

If the merger is completed, Bristol-Myers Squibb may fail to realize the anticipated benefits and cost savings of the merger, which could adversely affect the value of shares of Bristol-Myers Squibb common stock.

The success of the merger will depend, in part, on Bristol-Myers Squibb’s ability to realize the anticipated benefits and cost savings from combining the businesses of Bristol-Myers Squibb and Celgene. Bristol-Myers Squibb’s ability to realize these anticipated benefits and cost savings is subject to certain risks, including, among others:

If Bristol-Myers Squibb is not able to successfully combine the businesses of Bristol-Myers Squibb and Celgene within the anticipated time frame, or at all, the anticipated cost savings and other benefits of the merger may not be realized fully or may take longer to realize than expected, the combined businesses may not perform as expected and the value of the shares of Bristol-Myers Squibb common stock may be adversely affected.

Bristol-Myers Squibb and Celgene have operated and, until completion of the merger will continue to operate, independently, and there can be no assurances that their businesses can be integrated successfully. It is possible that the integration process could result in the loss of key Bristol-Myers Squibb or Celgene employees, the disruption of either company’s or both companies’ ongoing businesses or in unexpected integration issues, higher than expected integration costs and an overall post-completion integration process that takes longer than originally anticipated. Specifically, issues that must be addressed in integrating the operations of Celgene and Bristol-Myers Squibb in order to realize the anticipated benefits of the merger so the combined business performs as expected include, among others:

In addition, at times, the attention of certain members of each company’s management and each company’s resources may be focused on completion of the merger and the integration of the businesses of the two companies and diverted from day-to-day business operations, which may disrupt each company’s ongoing business and the business of the combined company.

Celgene’s executive officers and directors have interests in the merger that may be different from your interests as a stockholder of Celgene.

When considering the recommendation of the Celgene Board that Celgene stockholders vote in favor of the adoption of the merger agreement, Celgene stockholders should be aware that Celgene’s directors and executive officers have interests in the merger that may be different from, or in addition to, the interests of Celgene stockholders generally, including potential severance benefits, treatment of outstanding Celgene equity awards pursuant to the merger agreement and potential vesting of such awards in connection with a qualifying termination of employment on or following the merger (or, in certain circumstances, a termination of employment that otherwise occurs in connection with the merger), and rights to ongoing indemnification and insurance coverage. See “Interests of Celgene’s Directors and Executive Officers in the Merger” beginning on page 202 of this joint proxy statement/prospectus for a more detailed description of these interests. The Celgene Board and the BMS Board were aware of these interests and considered them, in addition to other matters, in evaluating and negotiating the merger agreement and in recommending that Celgene stockholders adopt the merger agreement and that the Bristol-Myers Squibb stockholders approve the stock issuance, respectively.

The merger agreement contains provisions that make it more difficult for Bristol-Myers Squibb and Celgene to pursue alternatives to the merger and may discourage other companies from trying to acquire Celgene for greater consideration than what Bristol-Myers Squibb has agreed to pay.

The merger agreement contains provisions that make it more difficult for Celgene to sell its business to a party other than Bristol-Myers Squibb, or for Bristol-Myers Squibb to sell its business. These provisions include a general prohibition on each party soliciting any acquisition proposal. Further, there are only limited exceptions to each party’s agreement that its board of directors will not withdraw or modify in a manner adverse to the other party the recommendation of its board of directors in favor of the adoption of the merger agreement, in the case of Celgene, or the approval of the stock issuance, in the case of Bristol-Myers Squibb, and the other party generally has a right to match any acquisition proposal that may be made. However, at any time prior to the adoption of the merger agreement by Celgene stockholders, in the case of Celgene, or the approval of the stock issuance by Bristol-Myers Squibb stockholders, in the case of Bristol-Myers Squibb, such party’s board of directors is permitted to make an adverse recommendation change if it determines in good faith that the failure to take such action would be reasonably likely to be inconsistent with its fiduciary duties under applicable law. In the event that either the Celgene Board or the BMS Board make an adverse recommendation change, then such party may be required to pay a $2.2 billion termination fee. Bristol-Myers Squibb and Celgene also will be required to pay certain transaction expenses and other costs incurred in connection with the merger, whether or not the merger is completed, including certain fees and expenses of the other party in connection with the Celgene fee reimbursement or the Bristol-Myers Squibb fee reimbursement, as applicable. See “The Merger

Agreement—No Solicitation” and “The Merger Agreement—Termination Fees and Expenses” beginning on pages 185 and 199, respectively, of this joint proxy statement/prospectus.

The parties believe these provisions are reasonable and not preclusive of other offers, but these restrictions might discourage a third party that has an interest in acquiring all or a significant part of either Celgene or Bristol-Myers Squibb from considering or proposing an acquisition proposal, even if that party were prepared to pay consideration with a higher per-share value than the currently proposed merger consideration, in the case of Celgene, or that party were prepared to enter into an agreement that may be favorable to Bristol-Myers Squibb or its stockholders, in the case of Bristol-Myers Squibb. Furthermore, the termination fees described above may result in a potential competing acquirer proposing to pay a lower per-share price to acquire the applicable party than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable by such party in certain circumstances.

The shares of Bristol-Myers Squibb common stock to be received by Celgene stockholders upon completion of the merger will have different rights from shares of Celgene common stock.

Upon completion of the merger, Celgene stockholders will no longer be stockholders of Celgene, but will instead become stockholders of Bristol-Myers Squibb, and their rights as Bristol-Myers Squibb stockholders will be governed by the terms of Bristol-Myers Squibb’s amended and restated certificate of incorporation, as it may be amended from time to time, which is referred to in this joint proxy statement/prospectus as Bristol-Myers Squibb’s certificate of incorporation, and Bristol-Myers Squibb’s amended and restated by-laws, as they may be amended from time to time, which are referred to in this joint proxy statement/prospectus as Bristol-Myers Squibb’s by-laws. The terms of Bristol-Myers Squibb’s certificate of incorporation and Bristol-Myers Squibb’s by-laws are in some respects materially different than the terms of Celgene’s certificate of incorporation, as they may be amended from time to time, which is referred to in this joint proxy statement/prospectus as Celgene’s certificate of incorporation, and Celgene’s amended and restated by-laws, as they may be amended from time to time, which are referred to in this joint proxy statement/prospectus as Celgene’s by-laws, which currently govern the rights of Celgene stockholders. See “Comparison of Stockholder Rights” beginning on page 225 of this joint proxy statement/prospectus for a discussion of the different rights associated with shares of Celgene common stock and shares of Bristol-Myers Squibb common stock.

Current Bristol-Myers Squibb stockholders and Celgene stockholders will have a reduced ownership and voting interest after the merger and will exercise less influence over the management of the combined company.

Upon completion of the merger, Bristol-Myers Squibb expects to issue approximately 701,024,507 shares of Bristol-Myers Squibb common stock to Celgene stockholders in connection with the transactions contemplated by the merger agreement. As a result, it is expected that, immediately after completion of the merger, former Celgene stockholders will own approximately 31% of the outstanding shares of Bristol-Myers Squibb common stock. In addition, shares of Bristol-Myers Squibb common stock may be issued from time to time following the effective time of the merger to holders of Celgene equity awards on the terms set forth in the merger agreement. See “The Merger Agreement—Treatment of Celgene Equity Awards” beginning on page 174 of this joint proxy statement/prospectus for a more detailed explanation. Consequently, current Bristol-Myers Squibb stockholders in the aggregate will have less influence over the management and policies of Bristol-Myers Squibb than they currently have over the management and policies of Bristol-Myers Squibb, and Celgene stockholders in the aggregate will have significantly less influence over the management and policies of Bristol-Myers Squibb than they currently have over the management and policies of Celgene.

Bristol-Myers Squibb and Celgene may be targets of transaction related lawsuits which could result in substantial costs and may delay or prevent the merger from being completed. If the merger is completed, Bristol-Myers Squibb will also assume Celgene’s risks arising from various legal proceedings.

Securities class action lawsuits and derivative lawsuits are often brought against public companies that have entered into merger agreements. Even if the lawsuits are without merit, defending against these claims can result in substantial costs and divert management time and resources. An adverse judgment could result in monetary damages, which could have a negative impact on Bristol-Myers Squibb’s and Celgene’s respective liquidity and financial condition. Additionally, if a plaintiff is successful in obtaining an injunction prohibiting completion of the merger, then that injunction may delay or prevent the merger from being completed, which may adversely

affect Bristol-Myers Squibb’s and Celgene’s respective business, financial position and results of operation. See “Litigation Relating to the Merger” beginning on page 170 of this joint proxy statement/prospectus for more information about litigation related to the merger that has been commenced prior to the date of this joint proxy statement/prospectus. There can be no assurance that additional complaints will not be filed with respect to the merger. Currently, with regard to the merger, Bristol-Myers Squibb and Celgene are not aware of any securities class action lawsuits or derivative lawsuits being filed.

One of the conditions to completion of the merger is the absence of any injunction or order being in effect that prohibits completion of the merger. Accordingly, if a plaintiff is successful in obtaining any injunction or order prohibiting the completion of the merger, then such injunction or order may prevent the merger from being completed, or from being completed within the expected timeframe.

In addition, if Bristol-Myers Squibb completes the merger, it will assume Celgene’s risks arising from legal proceedings. Like all pharmaceutical companies, Celgene is involved in various patent, product liability, consumer, commercial, securities, environmental and tax litigations and claims, government investigations and other legal proceedings that arise from time to time in the ordinary course of its business. Bristol-Myers Squibb cannot predict with certainty the eventual outcome of Celgene’s pending or future legal proceedings and the ultimate outcome of such matters could be material to the combined company’s results of operations, cash flows and financial condition.

The indebtedness of the combined company following completion of the merger will be substantially greater than Bristol-Myers Squibb’s indebtedness on a stand-alone basis and greater than the combined indebtedness of Bristol-Myers Squibb and Celgene existing prior to the announcement of the merger agreement. This increased level of indebtedness could adversely affect the combined company’s business flexibility, and increase its borrowing costs. Any resulting downgrades in Bristol-Myers Squibb’s and/or Celgene’s credit ratings could adversely affect Bristol-Myers Squibb’s, Celgene’s and/or the combined company’s respective businesses, cash flows, financial condition and operating results.

Bristol-Myers Squibb expects to incur acquisition-related debt financing of approximately $33.5 billion and assume Celgene’s existing indebtedness of approximately $19.9 billion (as of September 30, 2018). In addition, Celgene stockholders will receive one tradeable CVR for each share of Celgene representing the right to receive $9.00 in cash, which will entitle the holder to receive a payment upon the potential achievement of future U.S. regulatory milestones. Bristol-Myers Squibb also intends to enter into an accelerated share repurchase agreement to repurchase up to $5 billion of its common stock following completion of the merger. Bristol-Myers Squibb’s substantially increased indebtedness, any potential payments under the CVR and higher debt-to-equity ratio following completion of the merger in comparison to that of Bristol-Myers Squibb prior to the merger will have the effect, among other things, of reducing Bristol-Myers Squibb’s flexibility to respond to changing business and economic conditions, will increase Bristol-Myers Squibb’s borrowing costs and, to the extent that Bristol-Myers Squibb’s new debt is subject to floating interest rates, may increase Bristol-Myers Squibb’s vulnerability to fluctuations in market interest rates. In addition, the amount of cash required to service Bristol-Myers Squibb’s increased indebtedness levels and thus the demands on Bristol-Myers Squibb’s cash resources will be greater than the amount of cash flows required to service the indebtedness of Bristol-Myers Squibb or Celgene individually prior to the merger. The increased levels of indebtedness could also reduce funds available to fund Bristol-Myers Squibb’s efforts to combine its business with Celgene and realize expected benefits of the merger and/or engage in investments in product development, capital expenditures, dividend payments, share repurchases and other activities and may create competitive disadvantages for Bristol-Myers Squibb relative to other companies with lower debt levels. Bristol-Myers Squibb may be required to raise additional financing for working capital, capital expenditures, acquisitions or other general corporate purposes. Bristol-Myers Squibb’s ability to arrange additional financing or refinancing will depend on, among other factors, Bristol-Myers Squibb’s financial position and performance, as well as prevailing market conditions and other factors beyond Bristol-Myers Squibb’s control. Bristol-Myers Squibb cannot assure you that it will be able to obtain additional financing or refinancing on terms acceptable to Bristol-Myers Squibb or at all.

In addition, Bristol-Myers Squibb’s credit ratings impact the cost and availability of future borrowings, and, as a result, Bristol-Myers Squibb’s cost of capital. Bristol-Myers Squibb’s ratings reflect each rating organization’s opinion of Bristol-Myers Squibb’s financial strength, operating performance and ability to meet Bristol-Myers Squibb’s debt obligations or, following completion of the merger, obligations to the combined company’s insureds. Each of the ratings organizations reviews Bristol-Myers Squibb’s and Celgene’s ratings periodically, and

there can be no assurance that Bristol-Myers Squibb’s or Celgene’s current ratings will be maintained in the future. Following the announcement of the merger agreement, Moody’s placed certain of Bristol-Myers Squibb’s debt and other credit ratings under review for a possible downgrade and S&P Global Ratings placed the ratings of Bristol-Myers Squibb on credit watch with negative implications. Downgrades in Bristol-Myers Squibb’s and/or Celgene’s credit ratings could adversely affect Bristol-Myers Squibb’s, Celgene’s and/or the combined company’s businesses, cash flows, financial condition and operating results. In addition, if the merger is completed and, in certain circumstances, Celgene’s debt securities are downgraded and rated below investment grade, this may constitute a change of control triggering event under the indentures governing such debt. Upon the occurrence of a change of control triggering event, Celgene, as the surviving corporation of the merger, would be required to offer to repurchase most of its outstanding notes at 101% of the principal amount thereof plus accrued and unpaid interest if any, to, but not including, the date of repurchase. However, it is possible that Celgene (or Bristol-Myers Squibb) would not have sufficient funds at the time of the change of control triggering event to make the required repurchase of notes or that restrictions in other debt instruments would not allow such repurchases. Bristol-Myers Squibb and Celgene cannot provide any assurance that there will be sufficient funds available for Celgene (or Bristol-Myers Squibb) to make any required repurchases of the notes upon a change of control triggering event.

Bristol-Myers Squibb may not be able to service all of the combined company’s indebtedness and may be forced to take other actions to satisfy Bristol-Myers Squibb’s obligations under Bristol-Myers Squibb’s indebtedness, which may not be successful. Bristol-Myers Squibb’s failure to meet its debt service obligations could have a material adverse effect on the combined company’s business, financial condition and results of operations.

Bristol-Myers Squibb depends on cash on hand and cash flows from operations to make scheduled debt payments. Bristol-Myers Squibb expects to be able to meet the estimated cash interest payments on the combined company’s debt following the merger through a combination of the expected cash flows from operations of the combined company. However, Bristol-Myers Squibb’s ability to generate sufficient cash flow from operations of the combined company and to utilize other methods to make scheduled payments will depend on a range of economic, competitive and business factors, many of which are outside of Bristol-Myers Squibb’s control. There can be no assurance that these sources will be adequate. If Bristol-Myers Squibb is unable to service Bristol-Myers Squibb’s indebtedness and fund Bristol-Myers Squibb’s operations, Bristol-Myers Squibb will be forced to reduce or delay capital expenditures, seek additional capital, sell assets or refinance Bristol-Myers Squibb’s indebtedness. Any such action may not be successful and Bristol-Myers Squibb may be unable to service Bristol-Myers Squibb’s indebtedness and fund Bristol-Myers Squibb’s operations, which could have a material adverse effect on the combined company’s business, financial condition or results of operations.

Bristol-Myers Squibb will incur significant transaction and integration-related costs in connection with the merger. In addition, the merger may not be accretive, and may be dilutive, to Bristol-Myers Squibb’s earnings per share, which may negatively affect the market price of shares of Bristol-Myers Squibb’s common stock.

Bristol-Myers Squibb expects to incur a number of non-recurring costs associated with the merger and combining the operations of the two companies. Bristol-Myers Squibb will incur significant transaction costs related to the merger, including with respect to the financing for the cash consideration to be paid to Celgene stockholders. Bristol-Myers Squibb also will incur significant integration-related fees and costs related to formulating and implementing integration plans, including facilities and systems consolidation costs and employment-related costs. Bristol-Myers Squibb continues to assess the magnitude of these costs, and additional unanticipated costs may be incurred in the merger and the integration of the two companies’ businesses. While Bristol-Myers Squibb has assumed that a certain level of transaction expenses will be incurred, factors beyond Bristol-Myers Squibb’s control, such as certain of Celgene’s expenses, could affect the total amount or the timing of these expenses Although Bristol-Myers Squibb expects that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, should allow Bristol-Myers Squibb to offset integration-related costs over time, this net benefit may not be achieved in the near term, or at all.

In addition, future events and conditions could decrease or delay the accretion that is currently projected or could result in dilution, including adverse changes in market conditions, additional transaction and integration-related costs and other factors such as the failure to realize some or all of the anticipated benefits of the merger. Bristol-Myers Squibb plans to enter into an accelerated share repurchase program to repurchase up to $5 billion

of its common stock after the completion of the merger. In the event Bristol-Myers Squibb does not consummate such accelerated share repurchase program, stockholders may not realize the incremental accretive benefits associated with such accelerated share repurchase program. Any dilution of, decrease in or delay of any accretion to, Bristol-Myers Squibb’s earnings per share could cause the price of shares of Bristol-Myers Squibb common stock to decline or grow at a reduced rate.

Following the closing of the merger, a significant amount of the combined company’s total assets will be related to acquired intangible assets and goodwill, which are subject to annual impairment reviews, or more frequent reviews if events or circumstances indicate that the carrying value may not be recoverable. Because of the significance of these assets, any charges for impairment as well as amortization of intangible assets could have a material adverse effect on the combined company’s results of operations and financial condition.

The combined company will be subject to the risks that Celgene faces, in addition to the risks faced by Bristol-Myers Squibb. In particular, the success of the combined company will depend on its ability to obtain, commercialize and protect intellectual property and market exclusivity rights.

Celgene has a diverse early- and late-stage pipeline that includes five near-term product launch opportunities. The testing, manufacturing and marketing of these products requires regulatory approvals, including approval from the FDA and similar bodies in other countries. The future growth of the combined company would be negatively affected if Bristol-Myers Squibb, Celgene or the combined company fails to obtain requisite regulatory approvals within the expected time frames, or at all, in the United States and internationally for products in development and approvals for Bristol-Myers Squibb’s existing products for additional indications.

In addition, many of Celgene’s and Bristol-Myers Squibb’s drug candidates are in the early or mid-stages of research and development and will require the commitment of substantial financial resources, extensive research, development, preclinical testing, clinical trials, manufacturing scale-up and regulatory approval prior to being ready for sale. This process takes many years of effort without any assurance of ultimate success. If the combined company does not successfully develop and commercialize its pipeline candidates, the combined company’s financial position and results of operations could be adversely affected.

Celgene’s primary commercial stage products include REVLIMID ^® , POMALYST ^® /IMNOVID ^® , OTEZLA ^® , ABRAXANE ^® , VIDAZA ^® , azacitidine for injection (generic version of VIDAZA ^® ), THALOMID ^® (sold as THALOMID ^® or Thalidomide Celgene ^® outside of the United States) and IDHIFA. Upon the expiration or loss of patent protection for any of these products, or upon the “at-risk” launch (despite pending patent infringement litigation against the generic product) by a manufacturer of a generic version of one of these products, the combined company may quickly lose a significant portion of its sales of that product. Any such expiration or loss of patent protection with respect to REVLIMID ^® that occurs sooner than anticipated would be harmful to the combined company and could have a material adverse effect on its business, financial condition or results of operations.

The unaudited pro forma combined financial information and prospective financial information included in this joint proxy statement/prospectus are presented for illustrative purposes only and do not represent the actual financial position or results of operations of the combined company following completion of the merger or reflect the effect of any divestitures that may be required in connection with the merger.

The unaudited pro forma combined financial information and prospective financial information contained in this joint proxy statement/prospectus is presented for illustrative purposes only, contains a variety of adjustments, assumptions and preliminary estimates and does not represent the actual financial position or results of operations of Bristol-Myers Squibb and Celgene prior to the merger or that of the combined company following the merger for several reasons. Among other things, the unaudited pro forma combined financial information does not reflect the effect of any potential divestitures that may occur prior to or subsequent to completion of the merger, the projected realization of cost savings following completion of the merger or any changes in applicable law (including applicable tax law) after September 30, 2018. See the sections entitled “Certain Unaudited Pro Forma Condensed Combined Financial Statements,” “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Certain Unaudited Prospective Financial Information” and “Comparative Historical and Unaudited Pro Forma Combined Per Share Data” beginning on pages 58, 93 and 56, respectively, of this joint proxy statement/prospectus. The actual financial positions and results of operations of Celgene and Bristol-Myers Squibb prior to the merger and that of the combined company following the merger may not be consistent with, or evident from, the unaudited pro forma combined financial

information or prospective financial information included in this joint proxy statement/prospectus. In addition, the assumptions used in preparing the unaudited pro forma combined financial information and/or the prospective financial information included in this joint proxy statement/prospectus may not be realized and may be affected by other factors, which could lead to material changes to the combined company’s business that are not reflected in the unaudited pro forma combined financial information. Any significant changes in the market price of shares of Bristol-Myers Squibb common stock may cause a significant change in the purchase price used for Bristol-Myers Squibb’s accounting purposes and the pro forma combined financial information contained in this joint proxy statement/prospectus.

The opinions of Celgene’s and Bristol-Myers Squibb’s respective financial advisors do not reflect changes in circumstances that may have occurred or that may occur between the signing of the merger agreement and the completion of the merger.

Neither the Celgene Board, nor the BMS Board, has obtained updated opinions from their respective financial advisors as of the date of this joint proxy statement/prospectus, nor do any of them expect to receive updated, revised or reaffirmed opinions prior to the completion of the merger. Changes in the operations and prospects of Celgene or Bristol-Myers Squibb, general market and economic conditions and other factors that may be beyond the control of Celgene or Bristol-Myers Squibb, and on which Celgene’s and Bristol-Myers Squibb’s financial advisors’ opinions were based, may significantly alter the value of Celgene or Bristol-Myers Squibb or the share prices of Celgene common stock or Bristol-Myers Squibb common stock by the time the merger is completed. The opinions do not speak as of the time the merger will be completed or as of any date other than the date of such opinions. Because Celgene’s and Bristol-Myers Squibb’s financial advisors will not be updating their opinions, the opinions will not address the fairness of the merger consideration from a financial point of view at the time the merger is completed. The Celgene Board’s recommendation that Celgene stockholders approve the merger proposal and the BMS Board’s recommendation that Bristol-Myers Squibb stockholders approve the share issuance proposal, however, are made as of the date of this joint proxy statement/prospectus. For a description of the opinions that the Celgene Board and the BMS Board received from their respective financial advisors, see “The Merger Agreement—Opinions of Celgene’s Financial Advisors” and “The Merger Agreement—Opinions of Bristol-Myers Squibb’s Financial Advisors” beginning on pages 113 and 132, respectively, of this joint proxy statement/prospectus.

Certain Celgene agreements may contain change of control provisions that may have been triggered by the merger that, if acted upon or not waived, could cause the combined company to lose the benefit of such agreement and incur liabilities or replacement costs, which could have a material adverse effect on the combined company.

Celgene is party to, or may become party to after the date hereof, various agreements with third parties, including, among other agreements, certain license agreements, collaboration agreements, business development-related agreements, production and distribution related agreements, financing facilities, hedging arrangements, contracts for the performance of services material to the operations of Celgene and/or its affiliates and employment agreements that may contain change of control provisions that may be triggered upon the completion of the merger. Agreements with change of control provisions typically provide for or permit the termination of the agreement upon the occurrence of a change of control of one of the parties which can be waived by the relevant counterparties. In the event that there is such a contract or arrangement requiring a consent or waiver in relation to the merger or the merger agreement, for which such consent or waiver was not obtained, the combined company could lose the benefit of the underlying agreement and incur liabilities or replacement costs, which could have an adverse effect on the operations of the combined company.

The future results of the combined company may be adversely impacted if the combined company does not effectively manage its expanded operations following completion of the merger.

Following completion of the merger, the size of the combined company’s business will be significantly larger than the current size of either Bristol-Myers Squibb’s or Celgene’s respective businesses. The combined company’s ability to successfully manage this expanded business will depend, in part, upon management’s ability to implement an effective integration of the two companies and its ability to manage a combined business with significantly larger size and scope with the associated increased costs and complexity. There can be no assurances that the management of the combined company will be successful or that the combined company will realize the expected operating efficiencies, cost savings and other benefits currently anticipated from the merger.

Risks Related to the CVRs

You may not receive any payment on the CVRs.

Your right to receive any future payment on the CVRs will be contingent upon the achievement of certain agreed upon U.S. regulatory milestones within the time periods specified in the CVR agreement. If the CVR milestone, as defined in the section titled “Descriptions of the CVRs—Milestone Payment” starting on page 216 of this joint proxy statement/prospectus is not achieved for any reason within the time periods specified in the CVR agreement, no payment will be made under the CVRs, and the CVRs will expire valueless. Accordingly, the value, if any, of the CVRs is speculative, and the CVRs may ultimately have no value. See “Description of the CVRs” beginning on page 216 of this joint proxy statement/prospectus.

The U.S. federal income tax treatment of the CVRs is unclear.

Pursuant to the CVR agreement, the parties to the CVR agreement have agreed or will agree, as applicable, to treat and report the receipt of the CVR consideration for all tax purposes as additional consideration for the sale of Celgene common stock in the merger, except as required by applicable law. Assuming this treatment is correct, a later payment with respect to a CVR would likely be treated as a non-taxable return of a U.S. holder’s adjusted tax basis in the CVR to the extent thereof. A payment in excess of such amount may be treated as (i) a payment with respect to a sale of a capital asset or (ii) income taxed at ordinary rates. Additionally, a portion of a payment with respect to a CVR may constitute imputed interest under Section 483 of the Internal Revenue Code of 1986, as amended, which is referred to in this joint proxy statement/prospectus as the Code. In accordance with the CVR agreement, Bristol-Myers Squibb has agreed to report imputed interest on the CVRs pursuant to Section 483 of the Code, except as otherwise required by applicable law. However, the U.S. federal income tax treatment of the CVRs is unclear. There is no legal authority directly addressing the U.S. federal income tax treatment of the receipt of, and payments on, the CVRs, and there can be no assurance that the Internal Revenue Service, which is referred to in this joint proxy statement/prospectus as the IRS, would not assert, or that a court would not sustain a contrary position that could result in materially worse U.S. federal income tax consequences to holders. See “Celgene Proposal I: Adoption of the Merger Agreement and Bristol-Myers Squibb Proposal I: Approval of the Stock Issuance—Material U.S. Federal Income Tax Consequences” beginning on page 164 of this joint proxy statement/prospectus.

Any payments in respect of the CVRs are subordinated to the right of payment of Bristol-Myers Squibb’s other indebtedness.

The CVRs are unsecured obligations of Bristol-Myers Squibb and the CVR payments and all other obligations under the CVR agreement, together with the CVRs and any rights or claims relating thereto, are subordinated in right of payment to the prior payment in full of all senior obligations of Bristol-Myers Squibb. Senior obligations of Bristol-Myers Squibb include any existing or future obligations of Bristol-Myers Squibb, including the principal of, premium (if any), interest on, and all other amounts owing thereon with respect to borrowed money; evidenced by notes, debentures, bonds or other similar debt instruments; with respect to the net obligations owed under interest rate swaps or similar agreements or currency exchange transactions; as a result of reimbursement obligations in respect of letters of credit and similar obligations; in respect of capital leases; or as a result of guarantees in respect of obligations referred to above; unless, in any case, the instrument creating or evidencing the foregoing or pursuant to which the foregoing is outstanding provides that such obligations are pari passu to or subordinate in right of payment to the CVRs.

Bristol-Myers Squibb’s senior obligations do not include CVRs; trade debt incurred in the ordinary course of business; any intercompany indebtedness between Bristol-Myers Squibb and any of its subsidiaries or affiliates; indebtedness of Bristol-Myers Squibb that is subordinated in right of payment to Bristol-Myers Squibb’s senior obligations; indebtedness or other obligations of Bristol-Myers Squibb that by its terms ranks equal or junior in right of payment to the CVR payments and all other obligations under the CVR agreement; indebtedness of Bristol-Myers Squibb that, by operation of applicable law, is subordinate to any general unsecured obligations of Bristol-Myers Squibb; and indebtedness evidenced by any guarantee of indebtedness ranking equal or junior in right of payment to the CVR payments.

Upon any distribution to creditors of Bristol-Myers Squibb in liquidation, dissolution, bankruptcy, reorganization, insolvency, receivership or similar proceedings of Bristol-Myers Squibb, holders of senior obligations of Bristol-Myers Squibb (as described above) will be entitled to payment in full in cash of all such obligations prior to any payment being made on the CVRs. In addition, Bristol-Myers Squibb may not make any payment or distribution to any CVR holder of the CVR payments or other obligation under the CVR agreement or acquire from any CVR holder for cash any CVR, or propose the foregoing:

An active public market for the CVRs may not develop or the CVRs may trade at low volumes, both of which could have an adverse effect on the resale price, if any, of the CVRs.

The CVRs are a new security for which there is currently no public trading market. An active public trading market for the securities may not develop or be sustained. Bristol-Myers Squibb has agreed to use reasonable best efforts to cause the CVRs to be approved for listing at the completion of the merger on the NYSE or other national securities exchange and maintain such listing for as long as the CVRs remain outstanding. Notwithstanding its efforts, Bristol-Myers Squibb may be unable to cause the CVRs to be listed for trading.

Even if an active public trading market develops, there may be little or no market demand for the CVRs, making it difficult or impossible to resell the CVRs, which would have an adverse effect on the resale price, if any, of the CVRs. Immediately following the completion of the merger, the principal stockholders will hold a majority of the CVRs. In addition, holders of CVRs may incur brokerage charges in connection with the resale of the CVRs, which in some cases could exceed the proceeds realized by the holder from the resale of its CVRs. Neither Bristol-Myers Squibb nor Celgene can predict the price, if any, at which the CVRs will trade following the completion of the merger.

Because there has not been any public market for the CVRs, the market price and trading volume of the CVRs may be volatile.

Neither Celgene nor Bristol-Myers Squibb can predict the extent to which investor interest will lead to a liquid trading market in the CVRs or whether the market price of the CVRs will be volatile following the merger. The market price of the CVRs could fluctuate significantly for many reasons, including, without limitation:

Bristol-Myers Squibb’s obligation to achieve the CVR milestone is based on “diligent efforts,” which allows for consideration of a variety of factors to determine the efforts Bristol-Myers Squibb is required to take; accordingly, under certain circumstances Bristol-Myers Squibb may not be required to take certain actions to achieve the CVR milestone , or may allocate resources to other projects, which would have an adverse effect on the value, if any, of the CVRs.

Bristol-Myers Squibb has agreed to use “diligent efforts,” until the CVR agreement is terminated, to achieve the CVR milestone. However, the CVR agreement definition of “diligent efforts” allows for the consideration of a variety of factors in determining the efforts Bristol-Myers Squibb is required to use to obtain the CVR milestone, and it does not require Bristol-Myers Squibb to take all possible actions to achieve those goals.

The CVR agreement defines “diligent efforts” as, with respect to any product, efforts of a person to carry out its obligations in a diligent manner using such effort and employing such resources normally used by such person in the exercise of its reasonable business discretion relating to the research, development or commercialization of a product, that is of similar market potential at a similar stage in its development or product life, taking into account issues of market exclusivity (including patent coverage, regulatory and other exclusivity), safety and efficacy, product profile (including tolerability and convenience), the competitiveness of alternate products in the marketplace or under development, the launch or sales of one or more generic or biosimilar products, actual or likely pricing/reimbursement for the product, the likely timing of the product’s entry into the market, the likelihood of regulatory approval of the product and applicable labeling, and the profitability of the applicable product, and other relevant factors, including technical, commercial, legal, scientific, and/or medical factors, based on conditions then prevailing.

Risks R elat ed to Bristol-Myers Squibb and Celgene

Bristol-Myers Squibb and Celgene are, and following completion of the merger Bristol-Myers Squibb will continue to be, subject to the risks described in Part I, Item 1A in Bristol-Myers Squibb’s Annual Report on Form 10-K for the year ended December 31, 2017, filed with the SEC on February 13, 2018, and Part I, Item 1A in Celgene’s Annual Report on Form 10-K for the year ended December 31, 2017, filed with the SEC on February 7, 2018, as updated by their respective Quarterly Reports on Form 10-Q and future filings with the SEC, in each case, incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 250 of this joint proxy statement/prospectus.

COMPARATIVE HISTORICAL AND UNAUDITED
PRO FORMA COMBINED PER SHARE DATA

The following table sets forth selected historical and unaudited pro forma combined per share information for Bristol-Myers Squibb and Celgene.

Historical Per Share of Common Stock Information of Bristol-Myers Squibb and Celgene. The historical per share of common stock information of each of Bristol-Myers Squibb and Celgene below is derived from the audited consolidated financial statements of each of Bristol-Myers Squibb and Celgene as of and for the year ended December 31, 2017, and the unaudited consolidated financial statements of each of Bristol-Myers Squibb and Celgene as of and for the nine months ended September 30, 2018.

Unaudited Pro Forma Combined Per Bristol-Myers Squibb Share of Common Stock Data. The Bristol-Myers Squibb unaudited pro forma combined per share of common stock data set forth below gives effect to the merger under the acquisition method of accounting, as if the merger had been effective on January 1, 2017, the first day of Bristol-Myers Squibb’s fiscal year ended December 31, 2017, in the case of income from continuing operations per share. The unaudited pro forma combined book value per share of Bristol-Myers Squibb common stock data set forth below gives effect to the merger under the acquisition method of accounting, as if the merger had been effective September 30, 2018, assuming that each outstanding share of Celgene common stock had been converted into shares of Bristol-Myers Squibb common stock based on the exchange ratio.

The acquisition method of accounting is based on Financial Accounting Standards Board, Accounting Standards Codification, which is referred to in this joint proxy statement/prospectus as ASC 805, Business Combinations, which is referred to in this joint proxy statement/prospectus as ASC 805, and uses the fair value concepts defined in ASC 820, Fair Value Measurements, which is referred to in this joint proxy statement/prospectus as ASC 820, which Bristol-Myers Squibb has adopted as required. Acquisition accounting requires, among other things, that most assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Fair value measurements recorded in acquisition accounting are dependent upon certain valuation studies of Celgene’s assets and liabilities and other studies that have yet to commence or progress to a stage where there is sufficient information for a definitive measurement. Accordingly, the pro forma adjustments reflect the assets and liabilities of Celgene at their preliminary estimated fair values. Differences between these preliminary estimates and the final values in acquisition accounting will occur, and these differences could have a material impact on the unaudited pro forma combined per share information set forth in the following table.

The unaudited pro forma combined per share of Bristol-Myers Squibb common stock data is presented for illustrative purposes only and does not purport to represent the actual financial position or results of operations that Bristol-Myers Squibb would have achieved had the companies been combined during these periods or to project the future financial position or results of operations that Bristol-Myers Squibb may achieve after completion of the merger.

Unaudited Pro Forma Combined Per Celgene Equivalent Share Data. The Celgene unaudited pro forma combined per equivalent share data set forth below shows the effect of the merger from the perspective of an owner of shares of Celgene common stock. The information was calculated by multiplying the unaudited pro forma combined per share of Bristol-Myers Squibb common stock amounts by the exchange ratio.

Generally. You should read the below information in conjunction with the selected historical consolidated financial data included elsewhere in this joint proxy statement/prospectus and the historical consolidated financial statements of Bristol-Myers Squibb and Celgene and related notes that have been filed with the SEC, certain of which are incorporated by reference into this joint proxy statement/prospectus. See “Selected Historical Consolidated Financial Data of Bristol-Myers Squibb,” “Selected Historical Consolidated Financial Data of Celgene” and “Where You Can Find More Information” beginning on pages 52, 54 and 250, respectively, of this joint proxy statement/prospectus. The unaudited pro forma combined per share of Bristol-Myers Squibb common stock data and the unaudited pro forma combined per Celgene equivalent share data is derived from, and should be read in conjunction with, the Bristol-Myers Squibb and Celgene unaudited pro forma condensed combined financial statements and related notes included in this joint proxy statement/prospectus. See “Certain Unaudited Pro Forma Condensed Combined Financial Statements” beginning on page 58 of this joint proxy statement/prospectus.