Sec Form 4 Filing - Wolford Bernie G. @ DIAMOND OFFSHORE DRILLING, INC. - 2023-05-12

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 Wolford Bernie G. 2. Issuer Name and Ticker or Trading Symbol DIAMOND OFFSHORE DRILLING, INC. [ DO] 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) 15415 KATY FREEWAY, SUITE 100 3. Date of Earliest Transaction (MM/DD/YY) 05/12/2023 (Street) HOUSTON, TX77094 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 05/12/2023 M 39,219 A 728,151 D Common Stock 05/12/2023 F 15,433 D $ 11.58 712,718 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 ( 1 ) 05/12/2023 M 39,219 ( 2 ) ( 3 ) ( 3 ) Common Stock 39,219 ( 2 ) $ 0 78,436 ( 2 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Wolford Bernie G. 15415 KATY FREEWAY SUITE 100 HOUSTON, TX77094 X President and CEO Signatures /s/ Terence W. WaldorfAttorney-in-Fact forBernie G. Wolford 05/16/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Restricted stock units convert into common stock on a one-for-one basis. ( 2 )On May 16, 2022, the reporting person filed a Form 4 that reported that he was granted 116,769 restricted stock units on May 12, 2022, which inadvertently understated the number of restricted stock units that he was actually granted by 886 restricted stock units. This Form 4 correctly reflects that the reporting person was granted 117,655 restricted stock units on May 12, 2022, the first installment of which vested on May 12, 2023. ( 3 )The restricted stock units vest in three equal annual installments on May 12, 2023, May 12, 2024 and May 12, 2025. One share of common stock will be delivered with respect to each vested restricted stock unit within 30 days after the applicable vesting date.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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