Sec Form 4 Filing - Miller Larry R. @ SIGA TECHNOLOGIES INC - 2025-04-18

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 Miller Larry R. 2. Issuer Name and Ticker or Trading Symbol SIGA TECHNOLOGIES INC [ SIGA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) General Counsel (Last) (First) (Middle) C/O SIGA TECHNOLOGIES, INC., 31 EAST 62ND STREET 3. Date of Earliest Transaction (MM/DD/YY) 04/18/2025 (Street) NEW YORK, NY10065 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, par value $.0001 per share 04/18/2025 M( 1 ) 6,920 A $ 0 41,976 D Common Stock, par value $.0001 per share 04/18/2025 F 3,532 ( 2 ) D $ 5.99 38,444 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 Performa nce Stock Units ( 3 ) 04/18/2025 M( 1 ) 6,920 ( 1 ) ( 1 ) Common Stock, par value $.0001 per share 6,920 $ 0 13,841 D Performance Stock Units ( 3 ) 04/18/2025 D( 1 ) 13,841 ( 1 ) ( 1 ) Common Stock, par value $.0001 per share 13,841 $ 0 0 D Performance Stock Units ( 3 ) 04/18/2025 A( 1 ) 13,841 ( 1 ) ( 1 ) Common Stock, par value $.0001 per share 13,841 $ 0 13,841 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Miller Larry R. C/O SIGA TECHNOLOGIES, INC. 31 EAST 62ND STREET NEW YORK, NY10065 General Counsel Signatures /s/ Larry R. Miller 04/21/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On April 18, 2025, the Issuer's Board of Directors approved an amendment of the outstanding performance stock units ("PSUs") previously granted to the reporting person on March 25, 2024, to account for the Issuer's payment of a special cash dividend of $0.60 per share in April 2024 that would have applied to such PSUs based on the reporting person's actual period of service with the Issuer. As modified, the relevant stock price hurdles for these PSUs were each lowered by $0.60 such that (a) 6,920 PSUs vested immediately, (b) 6,920 PSUs vest if, during any period of 90 consecutive trading days during the three-year period beginning on the grant date (the "Performance Period"), the Issuer's Common Stock closing stock price (plus the per share value of any dividends declared during the measurement date) (the "Stock Price") is at or above $7.40, and (c) 6,921 PSUs vest, if during any 90 consecutive trading days during the Performance Period, the Stock Price is at or above $8.40. ( 2 )Represents the withholding by SIGA Technologies, Inc. of shares of Common Stock (based on $5.99 per share, the closing stock price on April 17, 2025) to satisfy tax withholding obligations associated with the vesting of PSUs and the consequent issuance of Common Stock. ( 3 )PSUs represent contingent rights to receive Common Stock on a one-for-one basis.

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).

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