Annexon, Inc. — Director's Dealing 2020

Jul 28, 2020

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Annexon, Inc. (ANNX)
CIK: 0001528115
Period of Report: 2020-07-28

Reporting Person: Bain Capital Life Sciences Investors, LLC (10% Owner)
Reporting Person: Bain Capital Life Sciences Fund, L.P. (10% Owner)
Reporting Person: BCIP Life Sciences Associates, LP (10% Owner)
Reporting Person: Koppel Adam (10% Owner)
Reporting Person: Bain Capital Life Sciences Partners, LP (10% Owner)
Reporting Person: Schwartz Jeffrey Lawrence (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2020-07-28	Common Stock	C	2522385	—	Acquired	2522385	Indirect
2020-07-28	Common Stock	C	319243	—	Acquired	2841628	Indirect
2020-07-28	Common Stock	P	400000	$17.00	Acquired	3241628	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2020-07-28	Series C Preferred Stock	$	C	22222221	Disposed		Common Stock (2522385)	Indirect
2020-07-28	Series D Preferred Stock	$	C	2812543	Disposed		Common Stock (319243)	Indirect

Footnotes

F1: Each share of Series C Preferred Stock ("Series C Stock") and Series D Preferred Stock ("Series D Stock") automatically converted on a 1-for-8.81 basis into the Issuer's Common Stock immediately prior to the closing of the Issuer's initial public offering.

F2: Represents 20,158,775 shares of Series C Stock held of record by Bain Capital Life Sciences Fund, L.P. ("BCLS") and 2,063,446 shares of Series C Stock held of record by BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS, the "Bain Capital Life Sciences Entities").

F3: Represents 2,551,384 shares of Series D Stock held of record by BCLS and 261,159 shares of Series D Stock held of record by BCIPLS.

F4: Represents 362,858 and 37,142 shares of the Issuer's Common Stock purchased by BCLS and BCIPLS, respectively, in the Issuer's initial public offering.

F5: Bain Capital Life Sciences Partners, LP ("BCLSP") is the general partner of BCLS. As a result, BCLSP may be deemed to share voting and dispositive power with respect to the securities held by BCLS. BCLSP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F6: Bain Capital Life Sciences Investors, LLC ("BCLSI"), whose managers are Jeffrey Schwartz and Adam Koppel, is the general partner of BCLSP and governs the investment strategy and decision-making process with respect to investments held by BCIPLS, whose general partner is Boylston Coinvestors, LLC. As a result, each of BCLSI, Mr. Schwartz and Dr. Koppel may be deemed to share voting and dispositive power over the shares held by the Bain Capital Life Sciences Entities. BCLSI, Mr. Schwartz and Dr. Koppel each disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein.