Tectonic Therapeutic (TECX) S-8Registration of securities for employees

Represents an additional 3,700,000 shares issuable under the 2018 Plan. These 3,700,000 shares represent an increase in the number of shares of common stock reserved for issuance under the 2018 Plan, which increase was approved by the Registrant’s stockholders on June 8, 2022 at the Registrant’s 2022 Annual Meeting of Stockholders. Shares available for issuance under the 2018 Plan were previously registered on a registration statement on Form S-8 filed with the Securities and Exchange Commission on June 21, 2018 (Registration No. 333-225788), March 25, 2019 (Registration No. 333-230494), March 16, 2020 (Registration No. 333-237203), August 6, 2020 (Registration No. 333-241400), March 18, 2021 (Registration No. 333-254466) and March 17, 2022 (Registration No. 333-263655).