Sec Form 4 Filing - MCGUIRE TERRANCE @ Adagio Therapeutics, Inc. - 2021-08-10

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person MCGUIRE TERRANCE 2. Issuer Name and Ticker or Trading Symbol Adagio Therapeutics, Inc. [ ADGI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ADAGIO THERAPEUTICS, INC., 303 WYMAN STREET, SUITE 300 3. Date of Earliest Transaction (MM/DD/YY) 08/10/2021 (Street) WALTHAM, MA02451 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 08/10/2021 C 2,852,425 A 2,852,425 I See Footnote ( 2 ) Common Stock 08/10/2021 P 267,769 A $ 17 3,120,194 I See Footnote ( 2 ) Common Stock 08/10/2021 C 55,595 A 55,595 I See Footnote ( 3 ) Common Stock 08/10/2021 P 5,219 A $ 17 60,814 I See Footnote ( 3 ) Common Stock 08/10/2021 C 19,540 A 19,540 I See Footnote ( 4 ) Common Stock 08/10/2021 P 1,834 A $ 17 21,374 I See Footnote ( 4 ) Common Stock 08/10/2021 C 28,520 A 28,520 I See Footnote ( 5 ) Common S tock 08/10/2021 P 2,678 A $ 17 31,198 I See Footnote ( 5 ) Common Stock 08/10/2021 C 4,755,460 A 4,755,460 I See Footnote ( 6 ) Common Stock 08/10/2021 P 45,000 A $ 17 4,800,460 I See Footnote ( 6 ) Common Stock 08/10/2021 C 320,160 A 320,160 I See Footnote ( 7 ) Common Stock 08/10/2021 P 177,500 A $ 17 497,660 I See Footnote ( 7 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Series A Preferred Stock ( 1 ) 08/10/2021 C 361,850 ( 1 ) ( 1 ) Common Stock 1,809,250 $ 0 0 I See Footnote ( 2 ) Series A Preferred Stock ( 1 ) 08/10/2021 C 7,052 ( 1 ) ( 1 ) Common Stock 35,260 $ 0 0 I See Footnote ( 3 ) Series A Preferred Stock ( 1 ) 08/10/2021 C 2,479 ( 1 ) ( 1 ) Common Stock 12,395 $ 0 0 I See Footnote ( 4 ) Series A Preferred Stock ( 1 ) 08/10/2021 C 3,619 ( 1 ) ( 1 ) Common Stock 18,095 $ 0 0 I See Footnote ( 5 ) Series A Preferred Stock ( 1 ) 08/10/2021 C 875,000 ( 1 ) ( 1 ) Common Stock 4,375,000 $ 0 0 I See Footnote ( 6 ) Series B Preferred Stock ( 1 ) 08/10/2021 C 85,061 ( 1 ) ( 1 ) Common Stock 425,305 $ 0 0 I See Footnote ( 2 ) Series B Preferred Stock ( 1 ) 08/10/2021 C 1,658 ( 1 ) ( 1 ) Common Stock 8,290 $ 0 0 I See Footnote ( 3 ) Series B Preferred Stock ( 1 ) 08/10/2021 C 583 ( 1 ) ( 1 ) Common Stock 2,915 $ 0 0 I See Footnote ( 4 ) Series B Preferred Stock ( 1 ) 08/10/2021 C 850 ( 1 ) ( 1 ) Common Stock 4,250 $ 0 0 I See Footnote ( 5 ) Series B Preferred Stock ( 1 ) 08/10/2021 C 44,076 ( 1 ) ( 1 ) Common Stock 220,380 $ 0 0 I See Footnote ( 6 ) Series C Preferred Stock ( 1 ) 08/10/2021 C 123,574 ( 1 ) ( 1 ) Common Stock 617,870 $ 0 0 I See Footnote ( 2 ) Series C Preferred Stock ( 1 ) 08/10/2021 C 2,409 ( 1 ) ( 1 ) Common Stock 12,045 $ 0 0 I See Footnote ( 3 ) Series C Preferred Stock ( 1 ) 08/10/2021 C 846 ( 1 ) ( 1 ) Common Stock 4,230 $ 0 0 I See Footnote ( 4 ) Series C Preferred Stock ( 1 ) 08/10/2021 C 1,235 ( 1 ) ( 1 ) Common Stock 6,175 $ 0 0 I See Footnote ( 5 ) Series C Preferred Stock ( 1 ) 08/10/2021 C 32,016 ( 1 ) ( 1 ) Common Stock 160,080 $ 0 0 I See Footnote ( 6 ) Series C Preferred ( 1 ) 08/10/2021 C 64,032 ( 1 ) ( 1 ) Common Stock 320,160 $ 0 0 I See Footnote ( 7 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other MCGUIRE TERRANCE C/O ADAGIO THERAPEUT ICS, INC. 303 WYMAN STREET, SUITE 300 WALTHAM, MA02451 X Signatures /s/ Dorothy Vinsky, Attorney-in-Fact 08/12/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share of Series A Preferred Stock, Series B Preferred Stock, and Series C Preferred Stock automatically converted, without payment of additional consideration, into Common Stock on a 5:1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock and had no expiration date. ( 2 )These shares are held of record by Polaris Venture Partners V, L.P. ("PVP V"). The general partner of PVP V is Polaris Venture Management Co. V, L.L.C. ("PVM V") and may be deemed to have shared voting and investment power with respect to the shares held by PVP V. The Reporting Person is a Managing Member of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVP V. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein. ( 3 )These shares are held of record by Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPEF V"). The general partner of PVPEF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPEF V. The Reporting Person is a Managing Member of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPEF V. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein. ( 4 )These shares are held of record by Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V"). The general partner of PVPFF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPFF V. The Reporting Person is a Managing Member of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPFF V. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein. ( 5 )These shares are held of record by Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V"). The general partner of PVPSFF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPSFF V. The Reporting Person is a Managing Member of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPSFF V. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein. ( 6 )These shares are held of record by Polaris Partners IX, L.P. ("PP IX"). The general partner of PP IX is Polaris Partners GP IX, L.L.C. ("PP GP IX") and may be deemed to have shared voting and investment power with respect to the shares held by PP IX. The Reporting Person holds an interest in PP GP IX and may be deemed to have shared voting and investment power with respect to the shares held by PP IX. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein. ( 7 )These shares are held of record by Polaris Healthcare Technology Opportunities Fund, L.P. ("PHCT"). The general partner of PHCT is Polaris Healthcare Technology Opportunities Fund GP, L.L.C. ("PHCT GP") and may be deemed to have shared voting and investment power with respect to the shares held by PHCT. The Reporting Person holds an interest in PHCT GP and may be deemed to have shared voting and investment power with respect to the shares held by PHCT. The Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of the Reporting Person's pecuniary interest therein. 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 Reporting Person is the beneficial owner of any securities reported herein.

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).

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