SAB Biotherapeutics CMO Alexandra Kropotova Withholds 473 Shares for Taxes

What Happened
Alexandra Kropotova, Chief Medical Officer of SAB Biotherapeutics (SABS), had 473 shares of common stock withheld on September 17, 2026 to satisfy tax withholding obligations arising from the vesting of restricted stock units (RSUs). The transaction is reported as a disposition for tax withholding purposes; no open-market sale or cash proceeds were reported and the per-share price is not applicable (N/A).

Key Details

• Transaction date: 2026-09-17; Form 4 filed 2026-09-18 (timely).
• Transaction type/code: Tax withholding on vesting of RSUs (code F).
• Shares withheld: 473 shares (used to satisfy tax withholding). Price: N/A.
• Shares owned after transaction: beneficially owns 38,402 shares of common stock and holds 3,433 RSUs that remain subject to vesting (total rights to 41,835 shares when including unvested RSUs per footnote).
• Footnotes: F1 = shares withheld to satisfy tax withholding on RSU vesting; F2 = breakdown of vested vs. unvested holdings; F3 = each RSU converts to one share.

Context
This is a routine tax-withholding action tied to RSU vesting and does not by itself signal a purchase or an opportunistic sale. For derivative clarity: each RSU represents the right to one share of common stock upon vesting; the withheld shares were applied to cover required taxes rather than sold on the open market.