X0508 4 2025-12-22 0001681087 Tectonic Therapeutic, Inc. TECX 0002023255 McNamara Peter C/O TECTONIC THERAPEUTIC, INC. 490 ARSENAL WAY, SUITE 210 WATERTOWN MA 02472 false true false false Chief Scientific Officer 0 Common Stock 2025-12-22 4 M 0 7000 2.98 A 40879 D Employee Stock Option (Right to Buy) 2.98 2025-12-22 4 M 0 7000 D 2032-06-26 Common Stock 7000 25065 D The shares subject to the option vest in 48 equal monthly installments beginning on June 27, 2022, subject to the Reporting Person's continued service to the Issuer on each such vesting date. Received in exchange for a stock option to acquire 60,000 shares of common stock pursuant to that certain merger, as more fully described on the Reporting Person's Form 4 filed with the Securities and Exchange Commission on June 24, 2024. https://www.sec.gov/Archives/edgar/data/1681087/000141588924017962/xslF345X05/form4-06242024_080611.xml /s/ Daniel Lochner, Attorney-in-Fact 2025-12-29