SERA PROGNOSTICS, INC.

Amended and Restated Executive Employment Agreements

On March 13, 2026, we entered into amended and restated executive employment agreements with all the Company’s executive officers and members of its senior management team, including the Company’s Chief Executive Officer (“CEO”) and the other executives with existing employment agreements (“Other Executives”). The purpose of the amendments was to make the agreements more consistent with each other and to adjust certain provisions. Because some of the Company’s executives who entered into amended and restated executive employment agreements are among those “officers” identified in Item 5.02(e) of Form 8-K, we are providing a summary of the material changes. Terms in uppercase below shall have the defined meanings ascribed to them in the amended and restated executive employment agreement, unless otherwise noted.

The amended and restated executive employment agreements address severance payments both in a non- Change of Control (“CIC”) context and in a CIC context. Specifically, upon termination by the Company not for Cause or termination by the executive for Good Reason outside of a CIC Protected Period (defined below), severance amounts are as follows: (1) an amount equal to the then current Base Salary for a period of 9 months for the Other Executives, and 12 months for the CEO, in each case payable on a payroll basis; and (2) continued health insurance coverage for 9 months for the Other Executives and 12 months for the CEO, or in each case, until the date the executive receives health insurance coverage in connection with new employment, if earlier. For any such termination within 3 months prior to or 12 months following a CIC (such period, a “CIC Protected Period”), severance amounts are as follows: (1) a lump sum payment in an amount equal to the sum of (a) the then current Base Salary for a period of 12 months for the Other Executives and 18 months for the CEO, plus (b) the full target Annual Bonus for the year of termination at a rate of 100% of target for the Other Executives and 150% of target for the CEO; and (2) continued health insurance coverage for 12 months for the Other Executives and 18 months for the CEO, or in each case, until the date the executive receives health insurance coverage in connection with new employment, if earlier.

The amended and restated executive employment agreements limit the existing partial equity acceleration in a non-CIC separation, while retaining the 100% equity acceleration in a “double trigger” CIC context. Specifically, upon a termination by the Company not for Cause or termination by the executive for Good Reason outside of a CIC Protected Period, vesting of 37.5% of any outstanding unvested equity awards granted prior to January 1, 2026 will be accelerated as provided in each executive’s previous employment agreement, with any such performance-based awards vesting at the target level of performance. Any Awards granted after January 1, 2026 shall not be accelerated in this circumstance. For any termination by the Company not for Cause or termination by the executive for Good Reason during a CIC Protected Period, all outstanding unvested equity awards will become fully vested as of the date of termination as provided in each executive’s previous employment agreement, with any performance-based awards vesting at the target level of performance, subject to the terms of our applicable equity plan.

In the previous agreements, an executive’s initial equity award became fully vested upon a mere CIC (to the extent not already vested) without any termination of employment. The amended and restated executive employment agreements eliminate this limited “single trigger” acceleration, while retaining the 100% equity acceleration in a “double trigger” CIC context.

Because some of the Company’s executives who entered into amended and restated executive employment agreements are among those “officers” identified in Item 5.02(e) of Form 8-K, we are also providing the current compensation information regarding Zhenya Lindgardt, President and Chief Executive Officer; John Boniface, Chief Scientific Officer; and Paul Kearney, Chief Data Officer, as set forth in their respective amended and restated executive employment agreement. The annual base salary for Ms. Lindgardt, Dr. Boniface and Dr. Kearney is set at $631,280, $453,621, and $444,822, respectively (the “Base Salary”), and they are each eligible to receive an annual discretionary cash bonus (the “Annual Bonus”) as determined by our board of directors or a committee thereof with a bonus target set at 40% of Base Salary for Dr. Boniface and Dr. Kearney, and 68% of Base Salary for Ms. Lindgardt. All the amended and restated executive employment agreements contain customary confidentiality, non-competition and non-solicitation provisions. The foregoing summary is qualified in its entirety by reference to the amendment and restated employment agreements, copies of which are filed as exhibits to this annual report on Form 10-K

2026 ATM Sales Agreement

On March 18, 2026, we entered into an at-the-market (“ATM”) sales agreement with William Blair & Company, L.L.C. (the “2026 ATM Sales Agreement”) and terminated the Company’s existing ATM sales agreement. This 2026 ATM Sales Agreement utilizes the available capacity under the Company’s existing Form S-3 shelf registration statement filed in August 2024 and is the subject of a prospectus supplement dated March 18, 2026. We are not obligated to make any sales of Class A common stock under the 2026 ATM Sales Agreement, but are now able to make sales under the ATM program in our discretion based on market conditions. No sales occurred under our prior ATM sales program.

Under the 2026 ATM Sales Agreement, we may offer and sell, from time to time at our sole discretion, shares of our Class A common stock, having an aggregate offering price of up to $40.0 million through William Blair, as sales agent. William Blair may sell the Class A common stock by any method that is deemed to be an “at the market offering” as defined in Rule 415(a)(4) of the Securities Act, including sales made directly on Nasdaq or any other existing trading market for the Class A common stock. William Blair will use commercially reasonable efforts, consistent with its normal sales and trading practices and applicable state and federal laws, rules and regulations and the rules of Nasdaq, to sell the Class A common stock from time to time, based upon instructions from us (including any price, time or size limits or other customary parameters or conditions we may impose). We will pay William Blair an aggregate of up to 3.0% of the gross proceeds of any shares of Class A common stock sold through William Blair under the 2026 ATM Sales Agreement and have provided William Blair with customary indemnification rights.

The foregoing description of the 2026 ATM Sales Agreement is qualified in its entirety by reference to the 2026 ATM Sales Agreement, a copy of which is filed as Exhibit 10.34 to this Annual Report. The legal opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. relating to the shares of Class A common stock being offered pursuant to the 2026 ATM Sales Agreement is filed as Exhibit 5.1 to this Annual Report.

This report shall not constitute an offer to sell or the solicitation of an offer to buy the securities discussed herein, nor shall there be any offer, solicitation, or sale of the securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

Rule 10b5-1 Trading Arrangements

During the quarter ended December 31, 2025, none of our executive 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. Certain of our Section 16 officers may participate in our 2021 ESPP that has been designed to comply with Rule 10b5-1(c).