Sec Form 4 Filing - DUFFY ROBERT L @ BWX Technologies, Inc. - 2024-02-27

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 DUFFY ROBERT L 2. Issuer Name and Ticker or Trading Symbol BWX Technologies, Inc. [ BWXT] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP and Chief Admin. Officer (Last) (First) (Middle) 800 MAIN STREET 3. Date of Earliest Transaction (MM/DD/YY) 02/27/2024 (Street) LYNCHBURG, VA24504 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 02/27/2024 M 94 A $ 0 4,729 D Common Stock 02/27/2024 F 94 ( 1 ) D $ 89.28 4,635 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 $ 0 02/27/2024 M 94 ( 2 ) ( 2 ) Common Stock 94 $ 0 2,174 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other DUFFY ROBERT L 800 MAIN STREET LYNCHBURG, VA24504 SVP and Chief Admin. Officer Signatures /s/ Robert L. Duffy by Theresa B. Taylor, attorney-in-fact 02/29/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The reported transaction includes the withholding of 94 shares of common stock converted to pay taxes associated with the deferral by the reporting person of a portion of the Restricted Stock Unit ("RSU") award vesting on February 27, 2024. ( 2 )RSUs vest in three equal annual installments beginning February 27, 2024. Each RSU represents the right to receive one share of the issuer's common stock. 756 of the RSUs vested on February 27, 2024, but the reporting person elected to defer receipt of shares underlying his vested RSUs. In accordance with his deferral election, vested shares will be delivered to the reporting person in a lump sum four years after termination of his employment with the issuer. 94 of the vested RSUs were converted to common stock to pay taxes associated with the deferral.

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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