[Form 4] Metsera, Inc. Insider Trading Activity

Rhea-AI Filing Summary

FMR LLC and related entities reported multiple transactions in Metsera, Inc. (MTSR) common stock on 09/02/2025. The filing shows net disposals and acquisitions across affiliated vehicles: 1,350,000 shares were disposed (reported as a distribution) and several affiliated entities recorded both purchases and disposals, including acquisitions of 997,312 and 1,134,258 shares and smaller transfers of 20,250, 895 and 997 shares. One open-market sale by Impresa Fund IV LLC shows 268 shares sold at $36 per share. After the reported transactions, FMR-affiliated holders report beneficial ownership positions such as 3,189,540 shares held indirectly. The filing is signed by Stephanie J. Brown on behalf of FMR LLC and Abigail P. Johnson.

Positive

• Transparency on ownership: Detailed remarks clarify relationships among FMR LLC, F-Prime, Impresa, and Abigail P. Johnson, aiding investor understanding.
• Material disclosure of holdings: The filing reports a substantial indirect beneficial position (3,189,540 shares), which is meaningful for market participants tracking insider ownership.

Negative

• Non-cash distributions: Large reported disposals (1,350,000 shares) are described as distributions without consideration, which may obscure economic intent compared with priced market transactions.
• Limited priced transactions: Only one small sale at $36 is explicitly priced, reducing clarity about the market valuation of the larger transfers.

Insights

Securities Analyst

TL;DR: Large affiliated transfers and a substantial indirect holding signal portfolio rebalancing within FMR-managed entities.

The Form 4 documents complex, largely intra-group transfers and a significant distribution of 1,350,000 Metsera shares reported as disposed without consideration, consistent with non-cash distributions among affiliated vehicles. Multiple affiliated funds show large acquisitions (notably 997,312 and 1,134,258 shares) recorded at $0, indicating transfers rather than market purchases. Beneficial ownership totals reported (for example, 3,189,540 shares indirect) quantify FMR's continuing material exposure in MTSR. The single small sale at $36 per share by Impresa Fund IV LLC is the only explicit priced transaction. This filing is transactional and structural rather than reporting new open-market accumulation.

Corporate Governance Expert

TL;DR: Reporting clarifies control relationships and ownership attribution among FMR, its subsidiaries, and the Johnson family.

Remarks disclose governance and ownership linkages: F-Prime entities, Impresa Management LLC, and F-Prime Inc. are described as managed or owned through FMR LLC structures, and Abigail P. Johnson's role and family voting arrangements are explicitly noted. These remarks explain why transfers are reported as indirect holdings and establish the basis for attributing beneficial ownership across the group. The filing includes a caution that the reporting does not concede legal beneficial ownership beyond Section 16 implications. This supports transparency on who controls or influences the reported MTSR positions.

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

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^*

FMR LLC

(Last) (First) (Middle)

245 SUMMER STREET

(Street)

BOSTON MA 02210

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Metsera, Inc. [ MTSR ]

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

	Director	X	10% Owner
	Officer (give title below)	X	Other (specify below)
			See Remark 1

3. Date of Earliest Transaction (Month/Day/Year)
09/02/2025

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

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

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

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	09/02/2025		J		1,350,000	D	$0(1)	3,189,540	I	F-Prime Capital Partners Life Sciences Fund VIII LP
Common Stock	09/02/2025		J		20,250	A	$0(1)	20,250	I	F-Prime Capital Partners Life Sciences Advisors Fund VIII LP
Common Stock	09/02/2025		J		20,250	D	$0(1)	0	I	F-Prime Capital Partners Life Sciences Advisors Fund VIII LP
Common Shares	09/02/2025		J		895	A	$0(1)	895	I	F-Prime Inc.
Common Stock	09/02/2025		J		997,312	A	$0(1)	997,312	I	Impresa Fund IV LLC
Common Stock	09/02/2025		J		997,044	D	$0(1)	268	I	Impresa Fund IV LLC
Common Stock	09/02/2025		S		268	D	$36	0	I	Impresa Fund IV LLC
Common Stock	09/02/2025		J		1,134,258	A	$0(1)	1,134,258	I	Shares held by persons and entities whose shares are subject to reporting by the undersigned.

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

Explanation of Responses:

1. These holdings were acquired or disposed of (as applicable) in the form of a distribution without payment of consideration.

Remarks:

Remark 1: Abigail P. Johnson is a Director, the Chairman and the Chief Executive Officer of FMR LLC. Members of the Johnson family, including Abigail P. Johnson, are the predominant owners, directly or through trusts, of Series B voting common shares of FMR LLC, representing 49% of the voting power of FMR LLC. The Johnson family group and all other Series B shareholders have entered into a shareholders' voting agreement under which all Series B voting common shares will be voted in accordance with the majority vote of Series B voting common shares. Accordingly, through their ownership of voting common shares and the execution of the shareholders' voting agreement, members of the Johnson family may be deemed, under the Investment Company Act of 1940, to form a controlling group with respect to FMR LLC. The address of Abigail P. Johnson is c/o FMR LLC, 245 Summer Street, Boston, MA 02110. Remark 2: The filing of this statement shall not be deemed to be an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the undersigned are the beneficial owners of any securities reported herein. Remark 3: F-Prime Capital Partners Life Sciences Advisors Fund VIII LP (FPCPLSA) is the general partner of F-Prime Capital Partners Life Sciences Fund VIII LP. FPCPLSA is solely managed by Impresa Management LLC, the managing member of its general partner and its investment manager. Impresa Fund IV LLC is solely managed by Impresa Management LLC, its general partner and investment manager. Impresa Management LLC is owned, directly or indirectly, by various shareholders and employees of FMR LLC, including certain members of the Johnson family. F-Prime Inc. is a wholly-owned subsidiary of FMR LLC.

	/s/ Stephanie J. Brown, Duly authorized under Powers of Attorney, by and on behalf of FMR LLC and its direct and indirect subsidiaries, and Abigail P. Johnson	09/04/2025
	** 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.

FAQ

What transactions in MTSR are reported on the Form 4?

The Form 4 reports multiple transactions on 09/02/2025 including a reported distribution disposal of 1,350,000 shares, acquisitions of 997,312 and 1,134,258 shares by affiliated entities, and a priced sale of 268 shares at $36.

Who filed the Form 4 for Metsera (MTSR)?

The Form 4 was filed by FMR LLC and signed by Stephanie J. Brown on behalf of FMR LLC and Abigail P. Johnson.

How many MTSR shares does FMR-affiliated ownership represent after these transactions?

The filing reports an example indirect beneficial ownership position of 3,189,540 shares following the reported transactions.

Are the transactions market purchases or transfers within affiliated entities?

Most reported entries are recorded at $0 and described as distributions or transfers, indicating they were non-cash internal transfers rather than market purchases; only one entry shows a market price ($36) for 268 shares.

What governance details are disclosed in the filing?

Remarks state that Abigail P. Johnson is Director, Chairman and CEO of FMR LLC, that the Johnson family holds Series B voting shares representing 49% of FMR LLC voting power, and that voting agreements affect Series B share voting.