Metsera, Inc. — Director's Dealing 2025

Jan 30, 2025

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Metsera, Inc. (MTSR)
CIK: 0002040807
Period of Report: 2025-01-30

Reporting Person: Burow Kristina (N/A)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1063955	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option (Right to Buy)	$8.18	2034-11-11	Common Stock (148953)		Direct
Series Seed Preferred Stock	$		Common Stock (8483268)		Indirect
Series A Convertible Preferred Stock	$		Common Stock (6383730)		Indirect
Series B Convertible Preferred Stock	$		Common Stock (1139951)		Indirect
Series A Convertible Preferred Stock	$		Common Stock (6383731)		Indirect
Series B Convertible Preferred Stock	$		Common Stock (1139951)		Indirect

Footnotes

F1: 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.

F2: The options were granted on November 12, 2024. The options vest and become exercisable in 36 substantially equal monthly installments following the grant date.

F3: 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 will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F4: 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 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.