Common stock, par value $0.0001 per share

Nautilus Biotechnology, Inc.

2701 Eastlake Avenue East, Seattle, WA, 98102

As of the date of this Schedule 13D, the Reporting Person beneficially owns an aggregate of 22,557,411 shares of Common Stock, or 17.6% of the Issuer's outstanding shares of Common Stock. The beneficial ownership percentages used in this Schedule are calculated based on a total of 126,564,473 shares of Common Stock outstanding as of February 19, 2026 plus 1,864,019 shares of Common Stock issuable upon exercise of options held by the Reporting Person. 1,234,018 of the Reporting Person's options to purchase shares of Common Stock are exercisable within 60 days of March 2, 2026. The unvested options to purchase shares of Common Stock vest over time subject to the Reporting Person's continued service through each vesting date. If, during the period beginning three months before a change in control through the one-year anniversary of a change in control, the Reporting Person's employment with the Issuer is terminated either (x) by the Issuer without cause, and excluding by reason of the Reporting Person's death or disability or (y) by the Reporting Person for good reason, then 100% of any unvested shares shall immediately vest.

The Reporting Person and the Reporting Person's spouse share voting and dispositive power with respect to 200,000 shares of Common Stock owned by the Foundation. The Reporting Person has sole voting and dispositive power with respect to 20,493,392 shares of Common Stock and options to purchase 1,864,019 shares of Common Stock.

On March 2, 2026, the Reporting Person was granted an option to purchase 280,000 shares of the Issuer's Common Stock. Except for such option grant, the Reporting Person has not effected any transactions in the Common Stock during the past 60 days.