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X0202 SCHEDULE 13D/A 0001104659-21-087437 0001725721 XXXXXXXX LIVE 1 Common Stock, par value $0.0001 per share 06/02/2026 false 0001808805 63909J108 Nautilus Biotechnology, Inc. 2701 Eastlake Avenue East Seattle WA 98102 a16z Capital Management (650) 798-3900 2865 Sand Hill Road, Suite 101 Menlo Park CA 94025 0001725721 N AH Bio Fund II, L.P. b WC N DE 11682032.00 0.00 11682032.00 0.00 11682032.00 N 9.2 PN 0001725722 N AH Equity Partners Bio II, L.L.C. b AF N DE 11682032.00 0.00 11682032.00 0.00 11682032.00 N 9.2 OO 0001829357 N Andreessen Horowitz LSV Fund II, L.P. b WC N DE 971885.00 0.00 971885.00 0.00 971885.00 N 0.8 PN 0001829384 N AH Equity Partners LSV II, L.L.C. b AF N DE 971885.00 0.00 971885.00 0.00 971885.00 N 0.8 OO 0001160077 N Marc L. Andreessen b AF N X1 0.00 12653917.00 0.00 12653917.00 12653917.00 N 9.9 IN 0001166586 N Benjamin A. Horowitz b AF N X1 0.00 12653917.00 0.00 12653917.00 12653917.00 N 9.9 IN Common Stock, par value $0.0001 per share Nautilus Biotechnology, Inc. 2701 Eastlake Avenue East Seattle WA 98102 This Amendment No. 1 (this "Amendment No. 1" or this "Schedule 13D/A") amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on June 30, 2021 (the "Statement") by AH Bio Fund II, L.P. ("AH Bio II"), AH Bio Fund II-B, L.P. ("AH Bio II-B"), AH Equity Partners Bio II, L.L.C. ("AH Equity Bio II"), Andreessen Horowitz LSV Fund II, L.P. ("AH LSV II"), Andreessen Horowitz LSV Fund II-B, L.P. ("AH LSV II-B"), Andreessen Horowitz LSV Fund II-Q, L.P. ("AH LSV II-Q"), AH Equity Partners LSV II, L.L.C. ("AH Equity LSV II"), Marc Andreessen ("Andreessen") and Benjamin Horowitz ("Horowitz"). Unless otherwise defined herein, capitalized terms used in this Amendment No. 1 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged. This Schedule 13D/A is filed by AH Bio II, AH Equity Bio II, AH LSV II, AH Equity LSV II, Andreessen and Horowitz. The foregoing entities and individuals are collectively referred to herein as the "Reporting Persons." AH Equity Bio II is the general partner of AH Bio II and may be deemed to have sole power to vote and sole power to dispose of shares of the Issuer held of record by AH Bio II for itself and as nominee for AH Bio II-B. Andreessen and Horowitz are managing members of AH Equity Bio II and may be deemed to have shared power to vote and shared power to dispose of shares of the Issuer held of record by AH Bio II for itself and as nominee. AH Equity LSV II is the general partner of AH LSV II and may be deemed to have sole power to vote and sole power to dispose of shares of the Issuer held of record by AH LSV II for itself and as nominee for AH LSV II-B and AH LSV II-Q. Andreessen and Horowitz are managing members of AH Equity LSV II and may be deemed to have shared power to vote and shared power to dispose of shares of the Issuer held of record by AH LSV II for itself and as nominee. The address of the principal place of business of each of the Reporting Persons is c/o Andreessen Horowitz, 2865 Sand Hill Road, Suite 101, Menlo Park, CA 94025. The principal occupation of each of Andreessen and Horowitz is as the co-founder and managing member of the venture capital firm Andreessen Horowitz. The principal business of each of the other Reporting Persons is the venture capital investment business. During the last five years, none of the Reporting Persons have been convicted in any criminal proceeding (excluding traffic violations or similar misdemeanors). During the last five years, none of the Reporting Persons have been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws. The responses of the Reporting Persons with respect to row 6 of their respective cover pages to this Schedule 13D/A are incorporated herein by reference. Rows 11 and 13 of each Reporting Person's cover page to this Schedule 13D/A set forth the aggregate number of shares of common stock and percentages of the shares of common stock beneficially owned by such Reporting Person and are incorporated by reference. The percentage set forth in each row 13 is based upon 127,078,855 shares of common stock outstanding as of April 23, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on April 28, 2026. Each of Messrs. Andreessen and Horowitz may be deemed to beneficially own 9.96% of the common stock as of the date of this filing. Due to field limitations of the EDGAR filing system, the percentages listed in Row 13 of the cover pages for each of Andreessen and Horowitz have been rounded down to 9.9%. Rows 7 through 10 of each Reporting Person's cover page to this Schedule 13D/A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition and are incorporated by reference. Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer during the past sixty days. On June 2, 2026, AH Bio II and AH LSV II sold 4,615,974 and 384,026 shares of common stock, respectively, in a single block trade at $2.35 per share. Under certain circumstances set forth in the limited partnership agreement of each of AH Bio II, AH Bio II-B, AH LSV II, AH LSV II-B, AH LSV II-Q and the limited liability company agreement of each of AH Equity Bio II and AH Equity LSV II the partners or members, as the case may be, of each of such entities may be deemed to have the right to receive dividends from, or the proceeds from the sale of, shares of the Issuer directly or indirectly owned by each such entity of which they are a partner or member. Not applicable. Exhibit 24.1 Power of Attorney (Marc Andreessen), dated June 23, 2023 Exhibit 24.2 Power of Attorney (Benjamin Horowitz), dated June 22, 2023 Exhibit 99.1 Joint Filing Agreement Exhibit 99.2 Amended and Restated Registration Rights and Lock-up Agreement, dated as of February 7, 2021, by and among ARYA Sciences Acquisition Corp III and the persons named therein (incorporated by reference to Exhibit 10.2 to the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission on February 8, 2021). Exhibit 99.3 Form of Subscription Agreement (incorporated by reference to Exhibit 10.3 to the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission on February 8, 2021) AH Bio Fund II, L.P. /s/ Phil Hathaway By AH Equity Partners Bio II, L.L.C., Its General Partner, By Phil Hathaway, Chief Operating Officer (See Note 1) 06/04/2026 AH Equity Partners Bio II, L.L.C. /s/ Phil Hathaway By Phil Hathaway, Chief Operating Officer 06/04/2026 Andreessen Horowitz LSV Fund II, L.P. /s/ Phil Hathaway By AH Equity Partners LSV II, L.L.C., Its General Partner, By Phil Hathaway, Chief Operating Officer (See Note 2) 06/04/2026 AH Equity Partners LSV II, L.L.C. /s/ Phil Hathaway By Phil Hathaway, Chief Operating Officer 06/04/2026 Marc L. Andreessen /s/ Phil Hathaway By Phil Hathaway, Attorney-in-Fact for Marc Andreessen 06/04/2026 Benjamin A. Horowitz /s/ Phil Hathaway By Phil Hathaway, Attorney-in-Fact for Benjamin Horowitz 06/04/2026 Note 1 AH Bio Fund II, L.P. for itself and as nominee for AH Bio Fund II-B, L.P. Note 2 Andreessen Horowitz LSV Fund II, L.P. for itself and as nominee for Andreessen Horowitz LSV Fund II-B, L.P. and Andreessen Horowitz LSV Fund II-Q, L.P.