Terrance McGuire - 07 Apr 2025 Form 4 Insider Report for Tectonic Therapeutic, Inc. (TECX)

Footnote F1

The reportable securities are owned directly by Polaris Partners IX, L.P. ("PP IX"). Polaris Partners GP IX, L.L.C. ("PP GP IX") is the general partner of PP IX. Each of David Barrett, Brian Chee, Amir Nashat and Amy Schulman are the managing members of PP GP IX (collectively, the "PP IX GP Managing Members"), and the Reporting Person, a member of the Issuer's board of directors, holds an interest in PP GP IX. Each of PP GP IX, the PP IX GP Managing Members and the Reporting Person, in their respective capacities with respect to PP GP IX, may be deemed to have shared voting, investment and dispositive power with respect to the securities held by PP IX, and each disclaims beneficial ownership of these securities, except to the extent of their respective pecuniary interests therein.

Footnote F2

The reportable securities are owned directly by Polaris Founders Capital I, LP. ("PFC I"). Polaris Founders Capital Management Co. I, L.L.C. ("PFCM I") is the general partner of PFC I. Each of the Reporting Person, a member of the Issuer's board of directors, and Jonathan Flint are the managing members of PFCM I (the "PFCM I Managing Members"). Each of PFCM I and the PFCM I Managing Members, in their respective capacities with respect to PFCM I, may be deemed to have shared voting, investment and dispositive power with respect to the securities held by PFC I, and each disclaims beneficial ownership of these securities, except to the extent of their respective pecuniary interests therein.

Footnote F3

The reportable securities are owned directly by Polaris Founders Capital II, LP. ("PFC II"). Polaris Founders Capital Management Co. I, L.L.C. ("PFCM II") is the general partner of PFC II. Each of the Reporting Person, a member of the Issuer's board of directors, and Jonathan Flint are the managing members of PFCM II (the "PFCM II Managing Members"). Each of PFCM II and the PFCM II Managing Members, in their respective capacities with respect to PFCM II, may be deemed to have shared voting, investment and dispositive power with respect to the securities held by PFC II, and each disclaims beneficial ownership of these securities, except to the extent of their respective pecuniary interests therein.