THOMAS FRANK E 4

What Happened Thomas Frank, a director of Spero Therapeutics (SPRO), received equity awards on June 23, 2026: 10,000 restricted stock units (RSUs) granted at $0.00 and a 20,000-share derivative award (reported as a grant) also at $0.00. The reported dollar value for both transactions is $0, indicating these were standard equity compensation grants rather than purchases or sales.

Key Details

• Transaction date(s) and price(s): 2026-06-23; both awards reported at $0.00 per share.
• Award types: 10,000 RSUs (F1) and a 20,000-share derivative award (F2) — the latter reported as an option/derivative grant.
• Vesting/exercise schedule: RSUs vest on June 23, 2027 subject to continued service (F1). The shares underlying the derivative award will vest and become exercisable in full on June 23, 2027 subject to continued service (F2).
• Shares owned after transaction: Not specified in the supplied filing details.
• Filing timeliness: Form 4 filed on 2026-06-25 for a 2026-06-23 transaction (filed within the typical two-business-day window).

Context

• RSUs: Each RSU represents the right to receive one share upon vesting; no shares are issued until vesting occurs and no cash changed hands at grant.
• Derivative award: Reported as a derivative grant (likely an option or similar instrument) that becomes exercisable on the stated vesting date; derivative grants differ from open-market purchases and do not imply immediate share ownership or sale.
• Interpretation: These are routine equity compensation grants to a director and do not represent an open-market buy or sell.