Andreessen Horowitz funds trim Nautilus (NAUT) stake with 5M-share open-market sale

Rhea-AI Filing Summary

Nautilus Biotechnology, Inc. disclosed that investment funds affiliated with Andreessen Horowitz executed open-market sales of common stock. AH Bio Fund II, L.P. sold 4,615,974 shares of common stock at $2.35 per share, leaving 11,682,032 shares of common stock held indirectly. Andreessen Horowitz LSV Fund II, L.P. sold 384,026 shares of common stock at $2.35 per share, with 971,885 shares of common stock remaining indirectly held. The funds are controlled through general partners AH Equity Partners Bio II, L.L.C. and AH Equity Partners LSV II, L.L.C., whose managing members are Marc Andreessen and Ben Horowitz, and the reporting persons disclaim group status and beneficial ownership beyond any pecuniary interest.

Insights

Equity ownership and insider-transactions analyst

Andreessen Horowitz–affiliated funds reported a net open-market sale of 5 million Nautilus Biotechnology shares.

Two investment funds associated with Andreessen Horowitz reported open-market sales totaling 5,000,000 shares of Nautilus Biotechnology common stock at $2.35 per share. These are non-derivative transactions and reduce the funds’ direct equity exposure while leaving sizable remaining positions.

AH Bio Fund II, L.P. now holds 11,682,032 shares, and Andreessen Horowitz LSV Fund II, L.P. holds 971,885 shares, both indirectly through their respective general partners. Footnotes state that Marc Andreessen and Ben Horowitz are managing members of those general partners.

The same footnotes emphasize that each reporting person disclaims the existence of a “group” and disclaims beneficial ownership of fund-held securities beyond any pecuniary interest. From an investor’s perspective, this points to a large but structured portfolio adjustment by institutional holders, without additional context on motive or timing.

Insider Trade Summary

Net Seller: 5,000,000 shares ($11,750,000)

Net Sell 2 txns

Insider AH Equity Partners Bio II, L.L.C., Andreessen Horowitz LSV Fund II, L.P., AH Bio Fund II, L.P., AH Equity Partners LSV II, L.L.C., Andreessen Marc L, HOROWITZ BENJAMIN A

Role null | null | null | null | null | null

Sold 5,000,000 shs ($11.75M)

Type	Security	Shares	Price	Value
Sale	Common Stock	4,615,974	$2.35	$10.85M
Sale	Common Stock	384,026	$2.35	$902K

Holdings After Transaction: Common Stock — 11,682,032 shares (Indirect, By AH Bio Fund II, L.P.)

Footnotes (1)

1. The reported securities are held by AH Bio Fund II, L.P. ("AH Bio Fund II"), for itself and as nominee for AH Bio Fund II-B, L.P. AH Equity Partners Bio II, L.L.C. ("AH EP Bio II") is the general partner of AH Bio Fund II and has sole voting and dispositive power with regard to the securities held by AH Bio Fund II for itself and as nominee. The managing members of AH EP Bio II are Marc Andreessen and Ben Horowitz. Marc Andreessen and Ben Horowitz may be deemed to share voting and dispositive power with respect to the securities held by AH Bio Fund II for itself and as nominee. Each of the Reporting Persons disclaims the existence of a "group" and disclaims beneficial ownership of the securities held by AH Bio Fund II for itself and as nominee (and this report shall not be deemed an admission that any such person is the beneficial owner of such securities), except to the extent of such person's pecuniary interest therein, if any. The reported securities are held by Andreessen Horowitz LSV Fund II, L.P. ("AH LSV Fund II"), for itself and as nominee for Andreessen Horowitz LSV Fund II-B, L.P. and Andreessen Horowitz LSV Fund II-Q, L.P. AH Equity Partners LSV II, L.L.C. ("AH EP LSV II") is the general partner of AH LSV Fund II and has sole voting and dispositive power with regard to the securities held by AH LSV Fund II for itself and as nominee. The managing members of AH EP LSV II are Marc Andreessen and Ben Horowitz. Marc Andreessen and Ben Horowitz may be deemed to share voting and dispositive power with respect to the securities held by AH LSV Fund II for itself and as nominee. Each of the Reporting Persons disclaims the existence of a "group" and disclaims beneficial ownership of the securities held by AH LSV Fund II for itself and as nominee (and this report shall not be deemed an admission that any such person is the beneficial owner of such securities), except to the extent of such person's pecuniary interest therein, if any.

Key Figures

Total shares sold: 5,000,000 shares Sale price: $2.35 per share AH Bio Fund II shares sold: 4,615,974 shares +3 more

6 metrics

Total shares sold 5,000,000 shares Net open-market sales on 2026-06-02

Sale price $2.35 per share Price for reported common stock sales

AH Bio Fund II shares sold 4,615,974 shares Common stock sold on 2026-06-02

AH Bio Fund II shares after sale 11,682,032 shares Indirect common stock holdings post-transaction

AH LSV Fund II shares sold 384,026 shares Common stock sold on 2026-06-02

AH LSV Fund II shares after sale 971,885 shares Indirect common stock holdings post-transaction

Key Terms

open-market sale, ten percent owner, beneficial ownership, pecuniary interest, +1 more

5 terms

open-market sale financial

"transaction_action: "open-market sale" for common stock on 2026-06-02"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

ten percent owner regulatory

"reporting persons each marked with "is_ten_percent_owner": 1"

beneficial ownership regulatory

"disclaims beneficial ownership of the securities held by AH Bio Fund II"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"except to the extent of such person's pecuniary interest therein, if any"

voting and dispositive power regulatory

"has sole voting and dispositive power with regard to the securities held"

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Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

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

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Nautilus Biotechnology, Inc. [ NAUT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/02/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/02/2026		S		4,615,974	D	$2.35	11,682,032	I	By AH Bio Fund II, L.P.(1)(2)
Common Stock	06/02/2026		S		384,026	D	$2.35	971,885	I	By Andreessen Horowitz LSV Fund II, L.P.(3)(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

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

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Andreessen Horowitz LSV Fund II, L.P.

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

AH Bio Fund II, L.P.

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

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

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Andreessen Marc L

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

HOROWITZ BENJAMIN A

(Last) (First) (Middle)

C/O ANDREESSEN HOROWITZ

2865 SAND HILL ROAD, SUITE 101

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. The reported securities are held by AH Bio Fund II, L.P. ("AH Bio Fund II"), for itself and as nominee for AH Bio Fund II-B, L.P. AH Equity Partners Bio II, L.L.C. ("AH EP Bio II") is the general partner of AH Bio Fund II and has sole voting and dispositive power with regard to the securities held by AH Bio Fund II for itself and as nominee. The managing members of AH EP Bio II are Marc Andreessen and Ben Horowitz. Marc Andreessen and Ben Horowitz may be deemed to share voting and dispositive power with respect to the securities held by AH Bio Fund II for itself and as nominee.

2. Each of the Reporting Persons disclaims the existence of a "group" and disclaims beneficial ownership of the securities held by AH Bio Fund II for itself and as nominee (and this report shall not be deemed an admission that any such person is the beneficial owner of such securities), except to the extent of such person's pecuniary interest therein, if any.

3. The reported securities are held by Andreessen Horowitz LSV Fund II, L.P. ("AH LSV Fund II"), for itself and as nominee for Andreessen Horowitz LSV Fund II-B, L.P. and Andreessen Horowitz LSV Fund II-Q, L.P. AH Equity Partners LSV II, L.L.C. ("AH EP LSV II") is the general partner of AH LSV Fund II and has sole voting and dispositive power with regard to the securities held by AH LSV Fund II for itself and as nominee. The managing members of AH EP LSV II are Marc Andreessen and Ben Horowitz. Marc Andreessen and Ben Horowitz may be deemed to share voting and dispositive power with respect to the securities held by AH LSV Fund II for itself and as nominee.

4. Each of the Reporting Persons disclaims the existence of a "group" and disclaims beneficial ownership of the securities held by AH LSV Fund II for itself and as nominee (and this report shall not be deemed an admission that any such person is the beneficial owner of such securities), except to the extent of such person's pecuniary interest therein, if any.

	AH Equity Partners Bio II, L.L.C., By /s/ Phil Hathaway, Chief Operating Officer	06/04/2026
	Andreessen Horowitz LSV Fund II, L.P., By AH Equity Partners LSV II, L.L.C., Its General Partner, By /s/ Phil Hathaway, Chief Operating Officer	06/04/2026
	AH Bio Fund II, L.P., By AH Equity Partners Bio II, L.L.C., Its General Partner, By /s/ Phil Hathaway, Chief Operating Officer	06/04/2026
	AH Equity Partners LSV II, L.L.C., By /s/ Phil Hathaway, Chief Operating Officer	06/04/2026
	/s/ Phil Hathaway, Attorney-in-Fact for Marc L. Andreessen	06/04/2026
	/s/ Phil Hathaway, Attorney-in-Fact for Benjamin Horowitz	06/04/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Nautilus Biotechnology (NAUT) report in this Form 4?

Nautilus Biotechnology reported that two Andreessen Horowitz–affiliated funds executed open-market sales of common stock. AH Bio Fund II, L.P. and Andreessen Horowitz LSV Fund II, L.P. together sold 5,000,000 shares at $2.35 per share, adjusting their indirect ownership stakes.

How many Nautilus Biotechnology (NAUT) shares did AH Bio Fund II, L.P. sell and retain?

AH Bio Fund II, L.P. reported selling 4,615,974 Nautilus Biotechnology common shares at $2.35 per share. After this transaction, AH Bio Fund II, L.P. is shown as indirectly holding 11,682,032 common shares, reflecting a substantial remaining position following the sale.

How many Nautilus Biotechnology (NAUT) shares did Andreessen Horowitz LSV Fund II, L.P. sell and retain?

Andreessen Horowitz LSV Fund II, L.P. reported selling 384,026 Nautilus Biotechnology common shares at $2.35 per share. After this open-market sale, the fund is shown as indirectly holding 971,885 common shares of Nautilus Biotechnology.

Who controls the Andreessen Horowitz funds trading Nautilus Biotechnology (NAUT) shares?

AH Equity Partners Bio II, L.L.C. and AH Equity Partners LSV II, L.L.C. act as general partners for the reporting funds. The filing states Marc Andreessen and Ben Horowitz are managing members of these entities and may share voting and dispositive power over the funds’ Nautilus holdings.

Do the Andreessen Horowitz reporting persons claim full beneficial ownership of Nautilus Biotechnology (NAUT) shares?

The filing states each reporting person disclaims the existence of a “group” and disclaims beneficial ownership of securities held by the funds, except to the extent of that person’s pecuniary interest. This limits the scope of ownership they acknowledge over Nautilus Biotechnology shares.

What is the net effect of this Form 4 on Andreessen Horowitz–related holdings in Nautilus Biotechnology (NAUT)?

The Form 4 shows a net sale of 5,000,000 Nautilus Biotechnology common shares by two Andreessen Horowitz–affiliated funds. Despite these sales, the funds together still hold over 12 million Nautilus common shares indirectly, according to the reported post-transaction balances.