Sec Form 4 Filing - O'Connor Daniel J. @ Ambrx Biopharma, Inc. - 2024-03-07

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person O'Connor Daniel J. 2. Issuer Name and Ticker or Trading Symbol Ambrx Biopharma, Inc. [ AMAM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President and CEO (Last) (First) (Middle) C/O AMBRX BIOPHARMA, INC., 10975 N TORREY PINES ROAD 3. Date of Earliest Transaction (MM/DD/YY) 03/07/2024 (Street) LA JOLLA, CA92037 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/07/2024 D 48,202 D 0 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Restricted Stock Units ( 3 ) 03/07/2024 D 294,643 ( 4 ) ( 4 ) Common Stock 294,643 ( 5 ) 0 D Restricted Stock Units ( 3 ) 03/07/2024 D 750,000 ( 6 ) ( 6 ) Common Stock 750,000 ( 5 ) 0 D Option to Purchase Common Stock $ 0.91 03/07/2024 D 772,857 ( 7 ) 10/31/2032 Common Stock 772,857 ( 8 ) 0 D Option to Purchase Common Stock $ 16.66 03/07/2024 D 173,785 ( 9 ) 07/05/2033 Common Stock 173,785 ( 8 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other O'Connor Daniel J. C/O AMBRX BIOPHARMA, INC. 10975 N TORREY PINES ROAD LA JOLLA, CA92037 X President and CEO Signatures /s/ Sonja Nelson, Attorney-in-Fact for Daniel J. O'Connor 03/07/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of January 5, 2024, among the Issuer, Johnson & Johnson ("J&J"), and Charm Merger Sub, Inc., a wholly owned subsidiary of J&J ("Merger Sub"), pursuant to which Merger Sub merged with and into the Issuer (the "Merger"), effective as of March 7, 2024 (such date and time of such Merger, the "Effective Time"), with the Issuer surviving the Merger as a wholly owned subsidiary of J&J. ( 2 )Pursuant to the Merger Agreement, at the Effective Time, each outstanding share of common stock of the Issuer ("Company Common Stock") reported in this Form 4 was converted into the right to receive an amount equal to $28.00 per share in cash (the "Merger Consideration"), without interest and less any applicable withholding taxes. ( 3 )Each of these restricted stock units ("RSUs") represents a contingent right to receive one share of the Company Common Stock. ( 4 )These RSUs vest as follows: (i) one-third (1/3) of the RSUs will vest on the 12-month anniversary of April 26, 2023 (the "Grant Date"), (ii) one-third (1/3) of the RSUs will vest on the 24-month anniversary of the Grant Date, and (iii) one-third (1/3) of the RSUs will vest on the 36-month anniversary of the Grant Date. ( 5 )Pursuant to the Merger Agreement, at the Effective Time, each of these RSUs that was outstanding as of immediately prior to the Effective Time was cancelled and the Reporting Person was entitled to receive the Merger Consideration, without interest and less any applicable withholding taxes, in respect of each such RSU. ( 6 )These RSUs vest as follows: (i) one-sixth (1/6) of the RSUs will vest on the six (6)-month anniversary of the grant date of December 11, 2023, and (ii) one-twelfth (1/12) of the RSUs will vest on a quarterly basis thereafter. ( 7 )The Company Common Stock subject to the options to purchase shares of Company Common Stock (each, a "Company Option") vest as follows: (i) twenty-five (25) percent of the Company Common Stock vested on November 1, 2023, and (ii) the remainder vests in thirty-six equal monthly installments following such date. ( 8 )Pursuant to the Merger Agreement, at the Effective Time, each Company Option that was outstanding and unexercised as of immediately prior to the Effective Time, whether vested or unvested, with a per share exercise price ("Per Share Exercise Price") that was less than the Merger Consideration, was cancelled and converted into the right to receive an amount in cash (without interest and less any applicable withholding taxes) equal to the product of (i) the aggregate number of shares of Company Common Stock underlying such Company Option immediately prior to the Effective Time, and (ii) the excess of (A) the Merger Consideration over (B) the Per Share Exercise Price of such Company Option. Each Company Option that had a Per Share Exercise Price that was equal to or exceeded the amount of the Merger Consideration at the Effective Time was cancelled for no consideration. ( 9 )The Company Common Stock subject to the Company Options vest as follows: (i) 1/6 of the Company Common Stock vested on January 5, 2024, and the remainder vests in ten (10) equal quarterly installments following such date.

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