SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* Bain Capital Life Sciences Investors, LLC (Last) (First) (Middle) 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 07/23/2020	3. Issuer Name and Ticker or Trading Symbol Annexon, Inc. [ ANNX ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series C Preferred Stock	(1)	(1)	Common Stock	22,222,221(1)	(1)	I	See Footnotes(3)(5)(6)
Series D Preferred Stock	(2)	(2)	Common Stock	2,812,543(2)	(2)	I	See Footnotes(4)(5)(6)

1. Name and Address of Reporting Person* Bain Capital Life Sciences Investors, LLC (Last) (First) (Middle) 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

1. Name and Address of Reporting Person* Bain Capital Life Sciences Partners, LP (Last) (First) (Middle) 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

1. Name and Address of Reporting Person* Bain Capital Life Sciences Fund, L.P. (Last) (First) (Middle) 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

1. Name and Address of Reporting Person* BCIP Life Sciences Associates, LP (Last) (First) (Middle) 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

1. Name and Address of Reporting Person* Koppel Adam (Last) (First) (Middle) C/O BAIN CAPITAL LIFE SCIENCES INVESTORS LLC, 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

1. Name and Address of Reporting Person* Schwartz Jeffrey Lawrence (Last) (First) (Middle) C/O BAIN CAPITAL LIFE SCIENCES INVESTORS LLC, 200 CLARENDON STREET (Street) BOSTON MA 02116 (City) (State) (Zip)

Explanation of Responses:

1. The shares of Series C Preferred Stock will automatically convert on a 1-for-8.81 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering.

2. The shares of Series D Preferred Stock will automatically convert on a 1-for-8.81 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering.

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

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

5. 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 their pecuniary interest therein.

6. 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.

Remarks:

	BAIN CAPITAL LIFE SCIENCES INVESTORS, LLC, By: /s/ Jeffrey Schwartz, Name: Jeffrey Schwartz, Title: Managing Director	07/23/2020
	BAIN CAPITAL LIFE SCIENCES PARTNERS, LP, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Jeffrey Schwartz, Name: Jeffrey Schwartz, Title: Managing Director	07/23/2020
	BAIN CAPITAL LIFE SCIENCES FUND, L.P., By: Bain Capital Life Sciences Partners, LP, its general partner, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Jeffrey Schwartz, Name: Jeffrey Schwartz, Title: Managing Director	07/23/2020
	BCIP LIFE SCIENCES ASSOCIATES, LP, By: Boylston Coinvestors, LLC, its general partner, By: /s/ Jeffrey Schwartz, Name: Jeffrey Schwartz, Title: Authorized Signatory	07/23/2020
	/s/ Adam Koppel	07/23/2020
	/s/ Jeffrey Schwartz	07/23/2020
	** Signature of Reporting Person	Date
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