Shaff Eric D. 4

What Happened
Eric D. Shaff, a director of Seres Therapeutics (MCRB), reported settlement of restricted stock units (RSUs) and a small open‑market sale on February 15, 2026. The Form 4 shows 723 shares acquired via exercise/conversion (RSU settlement). Separately, Shaff sold 259 shares in an open‑market transaction at $8.47 per share for proceeds of $2,194. The filing also reports two other exercise/conversion entries (391 and 333 shares) reported as disposed with $0 proceeds (see Key Details/footnotes).

Key Details

• Transaction date: February 15, 2026; Form 4 filed February 18, 2026 (no late‑filing flag indicated).
• Open‑market sale: 259 shares at $8.47, proceeds $2,194. Sale was effected under a Rule 10b5‑1 plan “solely with the intent to cover taxes” (Footnote F2).
• RSU settlement/exercise: 723 shares acquired via exercise/conversion (reported as “M”); additional 391 and 333 shares reported as exercise/conversion with $0 proceeds (these entries reflect share disposition/withholding in connection with RSU settlement as described in footnotes).
• Shares owned after the transactions: not specified in the provided filing data.
• Footnotes: F1 clarifies each RSU = right to one common share; F2 confirms the sale was under a 10b5‑1 plan to cover taxes; F3–F4 outline the RSU vesting schedule (25% vested Feb 15, 2024 and Feb 15, 2025, remainder vest quarterly thereafter; RSUs have no expiration).

Context
This activity reflects RSU settlement and routine tax‑related share disposition rather than an opportunistic open‑market investment: one small block (259 shares) was sold under a pre‑existing 10b5‑1 plan to cover taxes arising from vesting. The $2.2k sale amount is modest and does not by itself signal a material change in insider sentiment.