Metsera, Inc. — Director's Dealing 2025

Feb 3, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Metsera, Inc. (MTSR)
CIK: 0002040807
Period of Report: 2025-02-03

Reporting Person: ARCH Venture Partners XII, LLC (N/A)
Reporting Person: ARCH Venture Fund XII, L.P. (N/A)
Reporting Person: ARCH Venture Partners XII, L.P. (N/A)
Reporting Person: ARCH Venture Fund XIII, L.P. (N/A)
Reporting Person: ARCH Venture Partners XIII, L.P. (N/A)
Reporting Person: ARCH Venture Partners XIII, LLC (N/A)
Reporting Person: CRANDELL KEITH (N/A)
Reporting Person: GILLIS STEVEN (N/A)
Reporting Person: NELSEN ROBERT (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-02-03	Common Stock	C	16006949	—	Acquired	17070904	Indirect
2025-02-03	Common Stock	C	7523682	—	Acquired	7523682	Indirect
2025-02-03	Common Stock	P	1432224	$18	Acquired	18503128	Indirect
2025-02-03	Common Stock	P	789998	$18	Acquired	8313680	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-02-03	Series Seed Preferred Stock	$	C	19933333	Disposed		Common Stock (8483268)	Indirect
2025-02-03	Series A Convertible Preferred Stock	$	C	15000000	Disposed		Common Stock (6383730)	Indirect
2025-02-03	Series B Convertible Preferred Stock	$	C	2678571	Disposed		Common Stock (1139951)	Indirect
2025-02-03	Series A Convertible Preferred Stock	$	C	15000000	Disposed		Common Stock (6383731)	Indirect
2025-02-03	Series B Convertible Preferred Stock	$	C	2678571	Disposed		Common Stock (1139951)	Indirect

Footnotes

F1: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-for-2.349723. The preferred stock automatically converted into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F2: Represents shares held directly by ARCH Venture Fund XII, L.P ("ARCH Venture Fund XII"). ARCH Venture Partners XII, L.P. ("AVP XII LP"), as the sole general partner of ARCH Venture Fund XII, may be deemed to beneficially own the shares held by ARCH Venture Fund XII. ARCH Venture Partners XII, LLC ("AVP XII LLC"), as the sole general partner of AVP XII LP, may be deemed to beneficially own the shares held by ARCH Venture Fund XII. AVP XII LP and AVP XII LLC disclaim beneficial ownership except to the extent of any pecuniary interest therein. As members of the investment committee of AVP XII LLC, each of Kristina M. Burow, Keith Crandell, Steven Gillis and Robert Nelsen (the "AVP XII Committee Members") may also be deemed to share the power to direct the disposition and vote of the ARCH Venture Fund XII shares. Each AVP XII Committee Member disclaims beneficial ownership except to the extent of any pecuniary interest therein.

F3: Represents shares held directly by ARCH Venture Fund XIII, L.P.("ARCH Venture Fund XIII"). ARCH Venture Partners XIII, L.P. ("AVP XIII LP"), as the sole general partner of ARCH Venture Fund XIII, may be deemed to beneficially own the shares held by ARCH Venture Fund XIII. ARCH Venture Partners XIII, LLC ("AVP XIII LLC"), as the sole general partner of AVP XIII LP, may be deemed to beneficially own the shares held by ARCH Venture Fund XIII. AVP XIII LP and AVP XIII LLC disclaim beneficial ownership except to the extent of any pecuniary interest therein. As members of the investment committee of AVP XIII LLC, each of Paul L. Berns, Kristina M. Burow, Keith Crandell, Steven Gillis and Robert Nelsen (the "AVP XIII Committee Members") may also be deemed to share the power to direct the disposition and vote of the ARCH Venture Fund XIII shares. Each AVP XIII Committee Member disclaims beneficial ownership except to the extent of any pecuniary interest therein.

F4: (Continued from footnote 3) Each of Kristina Burow and Paul Berns has filed a separate Form 4.