SI-BONE, Inc. — Director's Dealing 2018

Oct 19, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: SI-BONE, Inc. (SIBN)
CIK: 0001459839
Period of Report: 2018-10-19

Reporting Person: ORBIMED ADVISORS LLC (Director)
Reporting Person: OrbiMed Capital GP V LLC (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2018-10-19	Common Stock	C	605964	—	Acquired	605964	Indirect
2018-10-19	Common Stock	C	179404	—	Acquired	785368	Indirect
2018-10-19	Common Stock	P	200000	$15.00	Acquired	985368	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-10-19	Series 6 Preferred Stock	$	C	572326	Disposed		Common Stock (605964)	Indirect
2018-10-19	Series 7 Preferred Stock	$	C	179404	Disposed		Common Stock (179404)	Indirect

Footnotes

F1: The Issuer's Series 6 Preferred Stock automatically converted into approximately 1.05878 shares of Issuer's common stock immediately upon
the closing of the Issuer's initial public offering and has no expiration date.

F2: Shares held by OrbiMed Private Investments V, LP. ("OPI V"). OrbiMed Capital GP V LLC ("GP V") is the general partner of OPI V and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP V. By virtue of such relationships, GP V and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI V and as a result may be deemed to have have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein. David P. Bonita, a member of the Issuer's board of directors, is an employee of OrbiMed Advisors.

F3: This report on Form 4 is jointly filed by GP V and OrbiMed Advisors. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity is a beneficial owner of such securities for purpose of Section 16 of the Exchange Act, or for any other purpose.

F4: The Issuer's Series 7 Preferred Stock automatically converted into an equal number of shares of Issuer's common stock immediately upon the closing of the Issuer's initial public offering and has no expiration date.