Joshua Pinto - 13 Nov 2025 Form 4 Insider Report for Metsera, Inc. (MTSR)

Role
Director
Signature
/s/ Matthew Lang, Attorney-in-Fact for Joshua Pinto
Issuer symbol
MTSR
Transactions as of
13 Nov 2025
Net transactions value
$0
Form type
4
Filing time
13 Nov 2025, 21:00:13 UTC
Previous filing
30 May 2025
Next filing
09 Jan 2026

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Pinto Joshua Director C/O METSERA, INC. 3 WORLD TRADE, CENTER 175 GREENWICH STREET, NEW YORK /s/ Matthew Lang, Attorney-in-Fact for Joshua Pinto 13 Nov 2025 0001992595

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MTSR Common Stock Disposed to Issuer -2,688 -100% 0 13 Nov 2025 Direct F1, F2, F5

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MTSR Restricted Stock Unit Award +2,688 2,688 13 Nov 2025 Common Stock 2,688 $0.000000 Direct F5
transaction MTSR Stock Option (right to buy) Disposed to Issuer -16,125 -100% 0 13 Nov 2025 Common Stock 16,125 $29.25 Direct F3, F4, F6
transaction MTSR Stock Option (right to buy) Disposed to Issuer -148,953 -100% 0 13 Nov 2025 Common Stock 148,953 $4.33 By LLC F3, F4, F7, F8
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Joshua Pinto is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id Content
F1 Pursuant to the Agreement and Plan of Merger dated September 21, 2025, as amended on November 7, 2025 (the "Merger Agreement"), by and among Metsera, Inc. (the "Company"), Pfizer Inc., a Delaware corporation ("Parent"), and Mayfair Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Parent (the "Merger Sub"), the Merger Sub merged with and into the Company, with the Company continuing as the surviving corporation and a wholly owned subsidiary of the Parent (the "Merger"). At the Effective Time of the Merger (as defined in the Merger Agreement), each issued and outstanding share of common stock, par value $0.00001 per share of the Company (the "Common Stock") was converted automatically into the right to receive (i) cash in an amount equal to $65.60 per share without interest (the "Closing Amount"), net of all applicable withholding taxes, plus (ii) one contractual contingent value right representing the right to receive contingent payments (a "CVR") in cash,
F2 (Continued from footnote 1) without interest, upon the achievement of certain specified milestones, in accordance with the terms and conditions of the contingent value rights agreement entered into by the Parent and Equiniti Trust Company, LLC, dated November 13, 2025 (collectively, the "Merger Consideration").
F3 Pursuant to the Merger Agreement, each outstanding and unexercised option immediately prior to the Effective Time, whether vested or unvested, was cancelled in exchange for the right to receive (x) an amount in cash equal to the product of (i) the excess, if any, of the Closing Amount minus the exercise price of such option, multiplied by (ii) the number of shares of Common Stock subject to such option immediately prior to the Effective Time, net of all applicable withholding taxes, and (y) one CVR for each share of the Common Stock subject to such stock option immediately prior to the Effective Time. In the case of any unvested stock options,
F4 (Continued from footnote 3) the cash payment and the CVRs are subject to the same vesting schedule terms as were applicable to the stock options, except that all such payments will become vested upon the first anniversary of the closing of the Merger, subject to the holder's continued service with the Parent or its subsidiaries through the first anniversary of the Merger.
F5 On November 12, 2025, the Reporting Person was granted restricted stock units ("RSUs") under the Company's 2025 Incentive Award Plan in a transaction exempt under Rule 16b-3. Each RSU represents a contingent right to receive one share of Common Stock. The RSUs vest in 36 substantially equal monthly installments from November 12, 2025. Pursuant to the Merger Agreement, all RSUs were cancelled and converted into the right to receive (x) an amount of cash equal to the Closing Amount multiplied by the number of shares of Common Stock subject to such RSU immediately prior to the Effective Time, net of all applicable withholding taxes, and (y) a number of CVRs equal to the under of the shares of Common Stock underlying the RSU. The cash payment and the CVRs are not subject to vesting.
F6 This option provided for vesting in 12 substantially equal monthly installments from May 20, 2025.
F7 This option provided for vesting in 36 substantially equal monthly installments from September 27, 2024.
F8 Reflects securities held by Maple DE Holdings LLC (the "LLC"). The units of the LLC are held by a trust for which the Reporting Person exercises investment control and is a beneficiary.