Nguyen Diem 4

4 · SIGA TECHNOLOGIES INC · Filed Jan 28, 2026

AI-generated summary of this filing

Updated Jan 29, 2026

SIGA CEO Nguyen Diem Receives RSU Shares; 22,804 Withheld

What Happened

Nguyen Diem, CEO of SIGA Technologies (SIGA), had one-third of his restricted stock units (RSUs) vest on January 27, 2026. The vesting converted 55,902 RSUs into 55,902 shares (exercise/conversion, code M) at $0.00 exercise price.
To satisfy tax withholding obligations, the issuer withheld 22,804 shares at the closing price of $6.82 on January 27, 2026 (code F), representing about $155,523. Net shares received by the CEO from this vesting event were 33,098 (55,902 vested − 22,804 withheld).
This was a routine award/vesting event (not an open-market purchase or sale); the acquisition required no cash outlay (exercise price $0).

Key Details

Transaction date: 2026-01-27; Form 4 filed: 2026-01-28 (timely).
Vesting/conversion: 55,902 RSUs → 55,902 shares (code M) at $0.00.
Tax withholding/sale to issuer: 22,804 shares withheld at $6.82/share → $155,523 (code F).
Net shares issued to insider: 33,098.
Footnotes: F1–F3 note these shares are from the one-third vesting of RSUs granted Jan 27, 2024; RSUs convert one-for-one and vest over three years; withholding was done by the issuer to satisfy taxes.
Shares owned after transaction: not specified in the provided excerpt.

Context

This was a standard RSU vesting with issuer share-withholding to cover taxes (often called a sell-to-cover), not an open-market sale or discretionary purchase — typically considered routine compensation-related activity rather than an explicit bullish or bearish trade signal.
Transaction codes: M = exercise/conversion of a derivative (RSU conversion), F = withholding to satisfy tax obligations.

Form 4

Period: 2026-01-27

DirectorChief Executive Officer

Transactions

Exercise/Conversion
Common Stock, par value $.0001 per share
[F1]
2026-01-27+55,902→ 123,555 total
Tax Payment
Common Stock, par value $.0001 per share
[F2]
2026-01-27$6.82/sh−22,804$155,523→ 100,751 total
Exercise/Conversion
Restricted Stock Units
[F3]
2026-01-27−55,902→ 55,903 total
→ Common Stock, par value $.0001 per share (55,902 underlying)

Footnotes (3)

[F1]Represents the acquisition of Common Stock from the vesting of one-third of the restricted stock units ("RSUs") granted on January 27, 2024.
[F2]Represents the withholding by the Issuer of shares of Common Stock (based on $6.82 per share, the closing stock price on January 27, 2026) to satisfy tax withholding obligations associated with the vesting of RSUs and the consequent issuance of Common Stock.
[F3]RSUs represent contingent rights to receive Common Stock on a one-for-one basis. The RSUs vest over three years, one-third on each of the first three anniversaries of the date of grant.

Signature

/s/ Diem Nguyen|2026-01-28

1 file