X0306 4 2017-11-09 false 0001114995 IMPINJ INC PI 0001219043 BYBEE CLINTON 8755 WEST HIGGINS SUITE 1025 CHICAGO IL 60631 true false false false COMMON STOCK 1366735 I See footnote COMMON STOCK 2017-11-09 4 P false 4000 24.43 A 4417 D 1,357,816 of these shares are held of record by ARCH Venture Fund V, L.P.; and 8,919 of these shares are held of record by ARCH V Entrepreneurs Fund, L.P. Clinton Bybee, a member of the board of directors, is a managing director of ARCH Venture Partners V, LLC, and may be deemed to beneficially own certain of the shares held of record by ARCH Venture Fund V, L.P. and ARCH V Entrepreneurs Fund, L.P. Mr. Bybee disclaims beneficial ownership of all shares held of record by ARCH Venture Fund V, L.P. and ARCH V Entrepreneurs Fund, L.P., of which he does not have an actual pecuniary interest. By virtue of their relationship as affiliated entities who have overlapping general partners and managing directors, ARCH Venture Fund V, L.P., ARCH V Entrepreneurs Fund, L.P., ARCH Venture Partners V, L.P., ARCH Venture Partners V, LLC and Mr. Bybee may be deemed to share the voting and investment control of the record shares. ARCH Venture Partners V, L.P., as the sole general partner of ARCH Venture Fund V, L.P. and ARCH V Entrepreneurs Fund, L.P., may be deemed to beneficially own certain of the shares held of record by ARCH Venture Fund V, L.P. and ARCH V Entrepreneurs Fund, L.P., but disclaims beneficial ownership of such shares, in which it does not have an actual pecuniary interest. ARCH Venture Partners V, LLC, as the sole general partner of ARCH Venture Partners V, L.P., may be deemed to beneficially own certain of the shares held of record by ARCH Venture Fund V, L.P. and ARCH V Entrepreneurs Fund, L.P. but disclaims beneficial ownership of such shares, in which it does not have an actual pecuniary interest. Yukio Morikubo, as Attorney-In-Fact for Clinton Bybee 2017-11-13