SERA PROGNOSTICS, INC.

Rule 10b5-1 Trading Arrangements

During the quarter ended December 31, 2024, none of the other officers (as defined in Section 16 of the Exchange Act) and directors adoptedor terminated any contract, instruction, or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense of Rule 10b5-1(c) or any “non-Rule 10b5-1 trading arrangement,” as defined in Item 408(a) of Regulation S-K.

Appointment of Jeffrey T. Elliot as Director

On March 17, 2025, our board of directors appointed Jeffrey T. Elliot, effective March 20, 2025 (the “Effective Date”), as a director to our board of directors to serve as a Class II Director with a term expiring at our 2026 Annual Meeting of Stockholders and as a member of the audit committee of the board of directors.

Mr. Elliot, age 47, has served as a Senior Advisor of Boston Consulting Group, a global consulting firm, since August 2024. Mr. Elliot has served on the board of directors of Quanterix Corporation (Nasdaq: QTRX), a publicly traded life sciences research and diagnostics company, since August 2024 and previously served on the board of directors of Exagen Inc. (Nasdaq: XGN), a publicly traded diagnostics company from March 2019 to July 2021. Prior to his current roles, Mr. Elliot was Chief Financial Officer of Exact Sciences Corporation, a molecular diagnostics company, from November 2016 to August 2024. Formerly, Mr. Elliott served as the Vice President, Business Development and Strategy of Exact Sciences from June 2016 to November 2016. From 2007 to 2016, Mr. Elliott was with Robert W. Baird & Co., where from June 2012 to June 2016 he was a senior research analyst who covered diagnostics and life science tools companies. Earlier in his career, Mr. Elliott worked in a supply chain role for Walgreens and as a consultant at Cap Gemini Ernst & Young. Mr. Elliott earned a B.S. in business administration from the University of Illinois at Urbana-Champaign and an M.B.A. from the University of Chicago Booth School of Business. Mr. Elliott is a CFA charterholder.

In connection with Mr. Elliot’s appointment to our board of directors, and pursuant to our Non-Employee Director Compensation Policy, on the Effective Date (the “Grant Date”), we will grant Mr. Elliot the lesser of (a) an equity award with a grant date fair value of $240,000, with approximately equal value coming from options and from restricted stock units (“RSUs”), or (b) an equity award of 100,000 option equivalents (the “Award”); where “option equivalents” means a specific number of shares, in the case of options, and a different number of RSUs that have value approximately equal to the fair market value of that specific number of options based on a Black-Scholes valuation method and rounded down to the nearest whole share. The Award shall have a per share exercise price for options equal to the fair market value (as defined in our 2021 Equity Incentive Plan) of our Class A common stock on the Grant Date. The Award will vest in thirty-six (36) substantially equal monthly installments following the Grant Date, subject to Mr. Elliot continuing to provide services to us through each such vesting.

In addition, Mr. Elliot is entitled to receive an annual cash retainer of $35,000 for his service as our non-employee director and $15,000 for his service as a member of the audit committee of the board of directors, pursuant to our Non-Employee Director Compensation Policy, prorated for the portion of the year that Mr. Elliot serves as a director.

Also in connection with Mr. Elliot’s appointment to the board of directors, we will enter into an indemnification agreement with Mr. Elliot in the form we have entered into with our other non-employee directors, which form is filed as Exhibit 10.1 to our Amendment No. 1 to our Registration Statement on Form S-1 (File No. 333-257038) filed by on July 8, 2021. Under this agreement, we will agree, among other things, to indemnify Mr. Elliot for certain expenses (including attorneys’ fees), judgments, fines and settlement amounts reasonably incurred by Mr. Elliot in any action or proceeding arising out of his service as one of our directors to the maximum extent allowed under Delaware law.

There are no arrangements or understandings between Mr. Elliot and any other person pursuant to which Mr. Elliot was appointed as a director. There are no transactions to which we are a party and in which Mr. Elliot has a material interest that are required to be disclosed under Item 404(a) of Regulation S-K. Mr. Elliot has not previously held any positions with us and has no family relations with any of our directors or executive officers.

Departure of Directors

On March 14, 2025, Ryan Trimble notified our board of directors of his decision to resign from our board of directors and any committees thereof, effective June 30, 2025. Mr. Trimble’s decision to resign was not due to any disagreement with the Company on any matter relating to the Company’s operations, policies or practices.

On March 17, 2025, Marcus Wilson, Pharm.D., notified our board of directors of his decision not to stand for re-election to the board of directors at the end of his current term at our 2025 annual meeting of stockholders currently expected to be held on June 5, 2025. Dr. Wilson’s decision not to stand for re-election was not due to any disagreement with the Company on any matter relating to the Company’s operations, policies or practices.