Whetstone Capital Advisors Acquires 8.6% Stake in Sera Prognostics, Inc.

Whetstone Capital Advisors, LLC and Mr. David Atterbury have filed a Schedule 13G/A with the SEC, indicating a significant increase in their holdings of Sera Prognostics, Inc. (SERA). As of the event date on March 31, 2026, the reporting persons beneficially own 3,306,889 shares of Class A Common Stock, representing an 8.6% ownership stake in the company. This filing marks an amendment to their previous position, which was reported at 0.0% ownership, reflecting a new substantial investment. Whetstone Capital Advisors, based in Kansas, and Mr. Atterbury share voting and dispositive power over the reported shares. The filing was made under Rule 13d-1(c), certifying that the securities were acquired in the ordinary course of business and not for the purpose of changing or influencing the control of the issuer. The total value of the reported holdings is approximately $6.42 million. This move positions Whetstone Capital Advisors as a major institutional investor in the Salt Lake City-based healthcare diagnostics company.