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Date of Report (Date of earliest event reported): December 6, 2023

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (801) 990-0520

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging Growth Company x

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o On December 6, 2023, Sera Prognostics, Inc. (the “Company”) entered into the second amendment (“Amendment No. 2”) to that certain Side Letter, dated as of April 29, 2021 (the “Side Letter”), previously amended effective February 16, 2023, with Baker Bros. Advisors LP and certain affiliates of Baker Bros. Advisors LP (collectively, “Baker Bros. Investors”). Pursuant to Amendment No. 2, the Baker Bros. Investors’ right to nominate one director to the Company’s board of directors was amended such that in order to exercise the right, among other conditions, the Baker Bros. Investors must beneficially own shares or other equity securities of the Company representing at least 19.9% of the then-outstanding total voting power of the Company.

The foregoing description of Amendment No. 2 does not purport to be complete and is qualified in its entirety by reference to Amendment No. 2, which will be filed as an exhibit to the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, and is incorporated herein by reference.

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Date: December 12, 2023