X0306 4 2021-03-11 false 0001459839 SI-BONE, Inc. SIBN 0001296771 Freund John Gordon C/O SKYLINE VENTURES 525 UNIVERSITY AVENUE, SUITE 1350 PALO ALTO CA 94301 true false false false Common Stock 2021-03-11 4 S false 63928.00 31.0465 D 1418118.00 I By Skyline Venture Partners V, LP Common Stock 2021-03-12 4 S false 91072.00 31.3912 D 1327046.00 I By Skyline Venture Partners V, LP Common Stock 2021-03-15 4 S false 80887.00 30.9022 D 1246159.00 I By Skyline Venture Partners V, LP Common Stock 100570.00 I By John Freund Family Partnership IV, L.P Shares held by SVP V. Skyline Venture Management V, LLC ("LLC") is the general partner of SVP V and as such may be deemed to have voting and investment power with respect to the securities of SVP V. Reporting Person, a member of Issuer's board of directors, is a managing director of LLC and may be deemed to have voting and investment power with respect to the securities held by SVP V. Reporting Person disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein. Shares held by John Freund Family Partnership IV, L.P. ("Family LP"). Reporting Person, a member of Issuer's board of directors, is a general partner of Family LP and may be deemed to have voting and investment power with respect to the securities held by Family LP. Reporting Person disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein. /s/ Michael A. Pisetsky, Attorney-in-Fact for John G. Freund 2021-03-15