X0508 4 2026-02-04 0001681087 Tectonic Therapeutic, Inc. TECX 0001757533 REICIN ALISE C/O TECTONIC THERAPEUTIC, INC. 490 ARSENAL WAY, SUITE 200 WATERTOWN MA 02472 true true false false Chief Executive Officer 0 Common Stock 2026-02-04 4 F 0 4104 23.22 D 235047 D Common Stock 124530 I By Trust This transaction reported represents the withholding of shares by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting and settlement of the restricted stock units granted on February 4, 2025. These shares are held by the Reicin-Boiarsky Family Trust (the "Trust"). The Reporting Person's spouse is a co-trustee of the Trust. Accordingly, the Reporting Person may be deemed to have shared voting and dispositive power over the securities held by the Trust. The Reporting Person disclaims beneficial ownership of the shares held by the Trust except to the extent of her pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose. /s/ Daniel Lochner, Attorney-in-Fact 2026-02-10