Brian Thomas reports 7.3% stake in Metagenomi

Metagenomi Therapeutics, Inc. (MGX) discloses that Brian Thomas has filed a Schedule 13G reporting beneficial ownership of 2,762,142 shares of its common stock, representing 7.3% of the class as of June 30, 2026.

Rhea-AI Filing Summary

Metagenomi Therapeutics, Inc. (MGX) discloses that Brian Thomas has filed a Schedule 13G reporting beneficial ownership of 2,762,142 shares of its common stock, representing 7.3% of the class as of June 30, 2026.

The position includes 2,433,969 shares held of record and 328,173 shares underlying stock options exercisable within 60 days of June 30, 2026. Based on 37,777,105 shares outstanding as of August 6, 2026, he has sole voting and dispositive power over all 2,762,142 reported shares.

Key Figures

Beneficially owned shares: 2,762,142 shares Percent of class: 7.3% Shares outstanding: 37,777,105 shares +3 more

6 metrics

Beneficially owned shares 2,762,142 shares Common stock beneficially owned by Brian Thomas as of June 30, 2026

Percent of class 7.3% Percentage of Metagenomi Therapeutics common stock class owned by Brian Thomas

Shares outstanding 37,777,105 shares Common stock outstanding as of August 6, 2026, per Form 10-Q

Shares held of record 2,433,969 shares Metagenomi Therapeutics common stock held of record by Brian Thomas

Stock options exercisable 328,173 shares Shares underlying stock options exercisable within 60 days of June 30, 2026

Sole voting and dispositive power 2,762,142 shares Shares over which Brian Thomas has sole voting and dispositive power

Key Terms

beneficial owner, Sole Voting Power, Sole Dispositive Power, stock options exercisable within 60 days

4 terms

beneficial owner financial

"The Reporting Person is deemed to be the beneficial owner of 2,762,142 shares"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

Sole Voting Power financial

"5 | Sole Voting Power 2,762,142.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Sole Dispositive Power financial

"7 | Sole Dispositive Power 2,762,142.00 8 | Shared Dispositive Power 0.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

stock options exercisable within 60 days financial

"328,173 shares of Common Stock subject to stock options exercisable within 60 days"

FAQ

What percentage of Metagenomi Therapeutics (MGX) shares does Brian Thomas report owning?

Brian Thomas reports beneficial ownership of 7.3% of Metagenomi Therapeutics’ common stock. This percentage is based on 37,777,105 shares outstanding as of August 6, 2026, as stated in the company’s Form 10-Q.

How many Metagenomi Therapeutics (MGX) shares does Brian Thomas beneficially own?

Brian Thomas is deemed the beneficial owner of 2,762,142 shares of Metagenomi Therapeutics common stock. This consists of 2,433,969 shares held of record and 328,173 shares underlying stock options exercisable within 60 days of June 30, 2026.

What is the basis for the ownership calculation in this Metagenomi Therapeutics (MGX) Schedule 13G?

The ownership percentage is calculated using 37,777,105 shares of Metagenomi Therapeutics common stock outstanding as of August 6, 2026, as reported in the company’s Form 10-Q filed on August 10, 2026.

What voting power does Brian Thomas report over Metagenomi Therapeutics (MGX) shares?

Brian Thomas reports sole voting power over 2,762,142 shares and no shared voting power. He also reports sole dispositive power over the same 2,762,142 shares and no shared dispositive power.

What portion of Brian Thomas’s Metagenomi Therapeutics (MGX) holdings comes from stock options?

Out of the 2,762,142 beneficially owned shares, 328,173 shares are subject to stock options that are exercisable within 60 days of June 30, 2026. The remaining 2,433,969 shares are held of record by Brian Thomas.

What is the reporting date and signature date on this Metagenomi Therapeutics (MGX) Schedule 13G?

The beneficial ownership information is stated as of June 30, 2026, and the Schedule 13G is signed by Brian Thomas on September 10, 2026.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/10/2026 - 04:06 PM Accepted by SEC EDGAR 09/10/2026 - 04:05 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Metagenomi Therapeutics, Inc.

(Name of Issuer)

Common stock, par value $0.0001 per share

(Title of Class of Securities)

59102M104

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 59102M104

1

Names of Reporting Persons

Thomas Brian C.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,762,142.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,762,142.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,762,142.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.3 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Metagenomi Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 5959 HORTON STREET, 7TH FLOOR, EMERYVILLE, CA, 94608
Item 2.
(a)	Name of person filing: This statement is filed on behalf of Brian Thomas (the "Reporting Person").
(b)	Address or principal business office or, if none, residence: The address of the principal business office of the Reporting Person is 126 The Uplands, Berkeley, CA 94705.
(c)	Citizenship: The Reporting Person is a citizen of the United States.
(d)	Title of class of securities: Common stock, par value $0.0001 per share
(e)	CUSIP Number(s): 59102M104
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: The ownership information below represents beneficial ownership of Common stock, par value $0.0001 per share ("Common Stock") of the Issuer as of June 30, 2026, based upon 37,777,105 shares of Common Stock outstanding as of August 6, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 10, 2026. The Reporting Person is deemed to be the beneficial owner of 2,762,142 shares of Common Stock, consisting of (i) 2,433,969 shares of Common Stock held of record by the Reporting Person and (ii) 328,173 shares of Common Stock subject to stock options exercisable within 60 days of June 30, 2026 by the Reporting Person.
(b)	Percent of class: 7.3%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 2,762,142
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2,762,142
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.	Certifications:
	Not Applicable

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.

Thomas Brian C.

Signature:	/s/ Brian Thomas
Name/Title:	Brian Thomas
Date:	09/10/2026