Terry P. Gould - 02 Aug 2021 Form 4 Insider Report for Icosavax, Inc.

Footnote F1

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.

Footnote F2

The shares are held directly by Adams Street Venture/Growth Fund VI LP ("ASVG VI").

Footnote F3

The shares are held directly by Adams Street Growth Equity Fund VII LP ("AS GE VII").

Footnote F4

The shares are held directly by Adams Street 2016 Direct Venture/Growth Fund LP ("AS 2016").

Footnote F5

The shares are held directly by Adams Street 2017 Direct Venture/Growth Fund LP ("AS 2017").

Footnote F6

The shares are held directly by Adams Street 2018 Direct Venture/Growth Fund LP ("AS 2018").

Footnote F7

The shares are held directly by Adams Street 2019 Direct Growth Equity Fund LP ("AS 2019").

Footnote F8

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.

Footnote F9

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.

Footnote F10

ASVG VI acquired additional shares in the Issuer's initial public offering.

Footnote F11

AS GE VII acquired additional shares in the Issuer's initial public offering.

Footnote F12

AS 2018 acquired additional shares in the Issuer's initial public offering.

Footnote F13

AS 2019 acquired additional shares in the Issuer's initial public offering.