Andreessen Horowitz trims Nautilus (NAUT) stake in June 2026 block trade

Rhea-AI Filing Summary

Andreessen Horowitz-affiliated funds filed Amendment No. 2 to a Schedule 13D for Nautilus Biotechnology, Inc. after a June 26, 2026 block trade at $2.00 per share.

AH Bio Fund II, L.P. now reports beneficial ownership of 8,366,966 common shares, or 6.6%, and Andreessen Horowitz LSV Fund II, L.P. reports 696,088 shares, or 0.5%. Marc Andreessen and Benjamin Horowitz each report shared beneficial ownership of 9,063,054 shares, or 7.1%, based on 127,078,855 common shares outstanding as of April 23, 2026.

Insights

Equity ownership analyst

Andreessen Horowitz updates its Nautilus stake after a June 2026 block sale.

The filing shows AH Bio Fund II and Andreessen Horowitz LSV Fund II executed a single block trade on June 26, 2026 at $2.00 per share. After this trade, they still hold multi-million-share positions in Nautilus Biotechnology.

AH Bio Fund II reports 8,366,966 shares, or 6.6%, and AH LSV II reports 696,088 shares, or 0.5%. Marc Andreessen and Benjamin Horowitz each report shared beneficial ownership of 9,063,054 shares, or 7.1%, based on 127,078,855 shares outstanding as of April 23, 2026. The filing is mainly an ownership update rather than a change in company fundamentals.

Key Figures

AH Bio Fund II ownership: 8,366,966 shares (6.6%) AH LSV Fund II ownership: 696,088 shares (0.5%) Andreessen shared ownership: 9,063,054 shares (7.1%) +4 more

7 metrics

AH Bio Fund II ownership 8,366,966 shares (6.6%) Beneficially owned common stock based on 127,078,855 shares outstanding as of April 23, 2026

AH LSV Fund II ownership 696,088 shares (0.5%) Beneficially owned common stock based on 127,078,855 shares outstanding as of April 23, 2026

Andreessen shared ownership 9,063,054 shares (7.1%) Marc Andreessen shared beneficial ownership percentage of common stock

Horowitz shared ownership 9,063,054 shares (7.1%) Benjamin Horowitz shared beneficial ownership percentage of common stock

Shares outstanding 127,078,855 shares Nautilus common stock outstanding as of April 23, 2026 from Form 10-Q

AH Bio Fund II sale 3,315,066 shares at $2.00/share Common stock sold in a single block trade on June 26, 2026

AH LSV Fund II sale 275,797 shares at $2.00/share Common stock sold in the same June 26, 2026 block trade

Key Terms

Schedule 13D, beneficially owned, block trade, Power of Attorney, +2 more

6 terms

Schedule 13D regulatory

"This Amendment No. 2 amends and supplements the statement on originally filed with the Securities and Exchange Commission"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

beneficially owned financial

"Rows 11 and 13 of each Reporting Person's cover page ... set forth the aggregate number of shares of common stock beneficially owned"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

block trade financial

"On June 26, 2026, AH Bio II and AH LSV II sold 3,315,066 and 275,797 shares ... in a single block trade at $2.00 per share."

A block trade is a large, privately arranged sale or purchase of a company's shares or bonds between big investors, often negotiated to avoid upsetting the public market price. Think of it like selling a truckload of goods directly to one buyer instead of unloading it on a busy street — it moves a lot of supply at once and can signal shifting demand, affect immediate liquidity, and influence short-term stock prices.

Power of Attorney regulatory

"Exhibit 24.1 Power of Attorney (Marc Andreessen), dated June 23, 2023"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

Registration Rights and Lock-up Agreement regulatory

"Exhibit 99.2 Amended and Restated Registration Rights and Lock-up Agreement, dated as of February 7, 2021"

Subscription Agreement financial

"Exhibit 99.3 Form of Subscription Agreement (incorporated by reference)"

A subscription agreement is a legal contract in which an investor agrees to buy a specific number of a company’s shares or other securities under set terms, including price, payment method and conditions for closing the sale. It matters to investors because it legally locks in their purchase and the company’s obligations, determines ownership percentage and any investor rights, and can include conditions or promises that affect future control or returns—like signing a detailed purchase order for equity.

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Available on EDGAR 06/30/2026 - 05:13 PM Accepted by SEC EDGAR 06/30/2026 - 05:13 PM Learn about SEC filing dates

FAQ

What does the latest Schedule 13D/A for Nautilus Biotechnology (NAUT) disclose?

The amended Schedule 13D reports updated Andreessen Horowitz-affiliated ownership in Nautilus Biotechnology. It reflects a June 26, 2026 block trade at $2.00 per share and restates current beneficial holdings and percentages based on 127,078,855 common shares outstanding.

How many Nautilus Biotechnology (NAUT) shares does AH Bio Fund II now beneficially own?

AH Bio Fund II, L.P. beneficially owns 8,366,966 Nautilus Biotechnology common shares. This represents 6.6% of the class, calculated using 127,078,855 shares outstanding as of April 23, 2026, as reported in Nautilus’s most recent Form 10-Q filing.

What Nautilus Biotechnology (NAUT) transaction occurred on June 26, 2026?

On June 26, 2026, AH Bio Fund II sold 3,315,066 shares and Andreessen Horowitz LSV Fund II sold 275,797 shares of Nautilus Biotechnology common stock. Both sales were executed in a single block trade at a price of $2.00 per share.

What stake in Nautilus Biotechnology (NAUT) do Marc Andreessen and Ben Horowitz report?

Marc Andreessen and Benjamin Horowitz each report shared beneficial ownership of 9,063,054 Nautilus Biotechnology common shares. This equates to 7.1% of the outstanding common stock, based on 127,078,855 shares outstanding as of April 23, 2026.

How many Nautilus Biotechnology (NAUT) shares are used to calculate the reported ownership percentages?

The ownership percentages are calculated using 127,078,855 Nautilus Biotechnology common shares outstanding. This figure comes from the company’s Form 10-Q, which stated that 127,078,855 common shares were outstanding as of April 23, 2026.

Who are the reporting persons in the Nautilus Biotechnology (NAUT) Schedule 13D/A?

Reporting persons include AH Bio Fund II, L.P., AH Equity Partners Bio II, L.L.C., Andreessen Horowitz LSV Fund II, L.P., AH Equity Partners LSV II, L.L.C., and individuals Marc Andreessen and Benjamin Horowitz. They are venture-capital-related entities and managers associated with Andreessen Horowitz.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 2)

Nautilus Biotechnology, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

63909J108

(CUSIP Number)

a16z Capital Management
2865 Sand Hill Road, Suite 101,
Menlo Park, CA, 94025
(650) 798-3900

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

06/26/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

AH Bio Fund II, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 8,366,966.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 8,366,966.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

8,366,966.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

6.6 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

AH Equity Partners Bio II, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 8,366,966.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 8,366,966.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

8,366,966.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

6.6 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

Andreessen Horowitz LSV Fund II, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 696,088.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 696,088.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

696,088.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.5 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

AH Equity Partners LSV II, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 696,088.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 696,088.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

696,088.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.5 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

Marc L. Andreessen

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 9,063,054.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 9,063,054.00

11

Aggregate amount beneficially owned by each reporting person

9,063,054.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.1 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 63909J108

1

Name of reporting person

Benjamin A. Horowitz

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 9,063,054.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 9,063,054.00

11

Aggregate amount beneficially owned by each reporting person

9,063,054.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.1 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: Nautilus Biotechnology, Inc.
(c)	Address of Issuer's Principal Executive Offices: 2701 Eastlake Avenue, East Seattle, WASHINGTON , 98102.
Item 1 Comment: This Amendment No. 2 (this "Amendment No. 2" 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 and amended on June 4, 2026 (as amended, the "Statement") by the Reporting Persons. Unless otherwise defined herein, capitalized terms used in this Amendment No. 2 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.
Item 2.	Identity and Background
(a)	This Schedule 13D/A is filed by AH Bio Fund II, L.P. ("AH Bio II"), AH Equity Partners Bio II, L.L.C. ("AH Equity Bio II"), Andreessen Horowitz LSV Fund II, L.P. ("AH LSV II"), AH Equity Partners LSV II, L.L.C. ("AH Equity LSV II"), Marc Andreessen ("Andreessen") and Benjamin Horowitz ("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.
(b)	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.
(c)	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.
(d)	During the last five years, none of the Reporting Persons have been convicted in any criminal proceeding (excluding traffic violations or similar misdemeanors).
(e)	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.
(f)	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.
Item 5.	Interest in Securities of the Issuer
(a)	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.
(b)	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.
(c)	Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer since the most recent amendment to the Statement filed with the SEC on June 4, 2026. On June 26, 2026, AH Bio II and AH LSV II sold 3,315,066 and 275,797 shares of common stock, respectively, in a single block trade at $2.00 per share.
(d)	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.
(e)	Not applicable.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 24.1 Power of Attorney (Marc Andreessen), dated June 23, 2023 (incorporated by reference to Exhibit 24.1 to the most recent amendment to the Statement filed with the SEC on June 4, 2026). Exhibit 24.2 Power of Attorney (Benjamin Horowitz), dated June 22, 2023 (incorporated by reference to Exhibit 24.2 to the most recent amendment to the Statement filed with the SEC on June 4, 2026). Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 to the most recent amendment to the Statement filed with the SEC on June 4, 2026). 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).

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

AH Bio Fund II, L.P.

Signature:	/s/ Phil Hathaway
Name/Title:	By AH Equity Partners Bio II, L.L.C., Its General Partner, By Phil Hathaway, Chief Operating Officer (See Note 1)
Date:	06/30/2026

AH Equity Partners Bio II, L.L.C.

Signature:	/s/ Phil Hathaway
Name/Title:	By Phil Hathaway, Chief Operating Officer
Date:	06/30/2026

Andreessen Horowitz LSV Fund II, L.P.

Signature:	/s/ Phil Hathaway
Name/Title:	By AH Equity Partners LSV II, L.L.C., Its General Partner, By Phil Hathaway, Chief Operating Officer (See Note 2)
Date:	06/30/2026

AH Equity Partners LSV II, L.L.C.

Signature:	/s/ Phil Hathaway
Name/Title:	By Phil Hathaway, Chief Operating Officer
Date:	06/30/2026

Marc L. Andreessen

Signature:	/s/ Phil Hathaway
Name/Title:	By Phil Hathaway, Attorney-in-Fact for Marc Andreessen
Date:	06/30/2026

Benjamin A. Horowitz

Signature:	/s/ Phil Hathaway
Name/Title:	By Phil Hathaway, Attorney-in-Fact for Benjamin Horowitz
Date:	06/30/2026

Comments accompanying signature:

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.