Sec Form 4 Filing - ADAMS STREET PARTNERS LLC @ Icosavax, Inc. - 2021-08-02

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 ADAMS STREET PARTNERS LLC 2. Issuer Name and Ticker or Trading Symbol Icosavax, Inc. [ ICVX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) Former 10% Owner (Last) (First) (Middle) ONE NORTH WACKER DRIVE, SUITE 2700 3. Date of Earliest Transaction (MM/DD/YY) 08/02/2021 (Street) CHICAGO, IL60606 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 08/02/2021 C 948,188 ( 9 ) A $ 0 ( 1 ) 948,188 ( 9 ) I See footnotes ( 2 ) ( 8 ) Common Stock 08/02/2021 P( 10 ) 47,981 A $ 15 996,169 I See footnotes ( 2 ) ( 8 ) Common Stock 08/02/2021 C 916,558 A $ 0 ( 1 ) 916,558 I See footnotes ( 3 ) ( 8 ) Common Stock 08/02/2021 P( 11 ) 46,381 A $ 15 962,939 I See footnotes ( 3 ) ( 8 ) Common Stock 08/02/2021 C 272,131 ( 9 ) A $ 0 ( 1 ) 272,131 ( 9 ) I See footnotes ( 4 ) ( 8 ) Common Stock 08/02/2021 C 352,037 A $ 0 ( 1 ) 352,037 I See footnotes ( 5 ) ( 8 ) Common Stock 08/02/2021 C 525,729 ( 9 ) A $ 0 ( 1 ) 525,729 ( 9 ) I See footnotes ( 6 ) ( 8 ) Common Stock 08/02/2021 P( 12 ) 26,604 A $ 15 552,333 I See footnotes ( 6 ) ( 8 ) Common Stock 08/02/2021 C 244,415 A $ 0 ( 1 ) 244,415 I See footnotes ( 7 ) ( 8 ) Common Stock 08/02/2021 P( 13 ) 12,368 A $ 15 256,783 I See footnotes ( 7 ) ( 8 )

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-1 Preferred Stock $ 0 08/02/2021 C 3,631,066 ( 1 ) ( 1 ) Common Stock 873,755 ( 1 ) 0 I See footnotes ( 2 ) ( 8 ) Series A-1 Preferred Stock $ 0 08/02/2021 C 3,509,939 ( 1 ) ( 1 ) Common Stock 844,608 ( 1 ) 0 I See footnotes ( 3 ) ( 8 ) Series A-1 Preferred Stock $ 0 08/02/2021 C 1,042,120 ( 1 ) ( 1 ) Common Stock 250,768 ( 1 ) 0 I See footnotes ( 4 ) ( 8 ) Series A-1 Preferred Stock $ 0 08/02/2021 C 1,348,119 ( 1 ) ( 1 ) Common Stock 324,402 ( 1 ) 0 I See footnotes ( 5 ) ( 8 ) Series A-1 Preferred Stock $ 0 08/02/2021 C 2,013,269 ( 1 ) ( 1 ) Common Stock 484,459 ( 1 ) 0 I See footnotes ( 6 ) ( 8 ) Series A-1 Preferred Stock $ 0 08/02/2021 C 935,985 ( 1 ) ( 1 ) Common Stock 225,229 ( 1 ) 0 I See footnotes ( 7 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 309,321 ( 1 ) ( 1 ) Common Stock 74,432 ( 1 ) 0 I See footnotes ( 2 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 299,003 ( 1 ) ( 1 ) Common Stock 71,950 ( 1 ) 0 I See footnotes ( 3 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 88,775 ( 1 ) ( 1 ) Common Stock 21,362 ( 1 ) 0 I See footnotes ( 4 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 114,843 ( 1 ) ( 1 ) Common Stock 27,635 ( 1 ) 0 I See footnotes ( 5 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 171,505 ( 1 ) ( 1 ) Common Stock 41,269 ( 1 ) 0 I See footnotes ( 6 ) ( 8 ) Series B-1 Preferred Stock $ 0 08/02/2021 C 79,734 ( 1 ) ( 1 ) Common Stock 19,186 ( 1 ) 0 I See footnotes ( 7 ) ( 8 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ADAMS STREET PARTNERS LLC ONE NORTH WACKER DRIVE SUITE 2700 CHICAGO, IL60606 Former 10% Owner Signatures /s/ Sara Robinson Dasse 08/03/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On August 2, 2021, the shares of Series A-1 Preferred Stock and Series B-1 Preferred Stock converted into shares of the Issuer's common stock at a ratio of 4.1557-for-1 automatically upon the closing of the Issuer's initial public offering without payment or further consideration. The shares have no expiration date. As a result of the Issuer's initial public offering, the reporting person is no longer a 10% owner of the Issuer and is therefore no longer subject to Section 16 in connection with its transactions in the equity securities of the Issuer. ( 2 )The shares are held directly by Adams Street Venture/Growth Fund VI LP ("ASVG VI"). ( 3 )The shares are held directly by Adams Street Growth Equity Fund VII LP ("AS GE VII"). ( 4 )The shares are held directly by Adams Street 2016 Direct Venture/Growth Fund LP ("AS 2016"). ( 5 )The shares are held directly by Adams Street 2017 Direct Venture/Growth Fund LP ("AS 2017"). ( 6 )The shares are held directly by Adams Street 2018 Direct Venture/Growth Fund LP ("AS 2018"). ( 7 )The shares are held directly by Adams Street 2019 Direct Growth Equity Fund LP ("AS 2019"). ( 8 )Adams Street Partners, LLC as the managing member of the general partner of the general partner of ASVG VI, AS GE VII, AS 2016, AS 2017, AS 2018 and AS 2019 (collectively the "Funds"), may be deemed to beneficially own the shares held by the Funds. Thomas S. Bremner, Jeffrey T. Diehl, Elisha P. Gould III, Robin P. Murray and Fred Wang, each of whom is a partner of Adams Street Partners, LLC (or a subsidiary thereof), may be deemed to have shared voting and investment power over the shares held by the Funds. Adams Street Partners, LLC and Thomas S. Bremner, Jeffrey T. Diehl, Elisha P. Gould, Robin Murray and Fred Wang disclaim beneficial ownership of the shares held by the Funds except to the extent of their pecuniary interest therein. ( 9 )Includes additional shares of Common Stock as a result of the conversion of Preferred Stock calculated on an aggregate basis of all shares of Preferred Stock held by the holder. ( 10 )ASVG VI acquired additional shares in the Issuer's initial public offering. ( 11 )AS GE VII acquired additional shares in the Issuer's initial public offering. ( 12 )AS 2018 acquired additional shares in the Issuer's initial public offering. ( 13 )AS 2019 acquired additional shares in the Issuer's initial public offering.

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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