SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

EVNIN ANTHONY B

(Last)

(First)

(Middle)

C/O VENROCK

530 FIFTH AVENUE, 22ND FLOOR

(Street)

NEW YORK

10036

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
ACCELERON PHARMA INC [ XLRN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/24/2013

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	09/24/2013		C		1,376,249	A	⁽¹⁾	1,385,981	I	By Funds⁽³⁾⁽¹⁰⁾
Common Stock	09/24/2013		C		507,665	A	⁽¹⁾	1,893,646	I	By Funds⁽³⁾⁽¹¹⁾
Common Stock	09/24/2013		C		293,143	A	⁽¹⁾	2,186,789	I	By Funds⁽³⁾⁽¹²⁾
Common Stock	09/24/2013		C		39,175	A	⁽¹⁾	2,225,964	I	By Funds⁽³⁾⁽¹³⁾
Common Stock	09/24/2013		J		190,571	A	⁽⁷⁾	2,416,535	I	By Funds⁽³⁾⁽¹⁴⁾
Common Stock	09/24/2013		C		79,617	A	⁽¹⁾	2,496,152	I	By Funds⁽³⁾⁽¹⁵⁾

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Series A Convertible Preferred Stock	⁽¹⁾	09/24/2013		C			1,376,249	⁽¹⁾	⁽¹⁾	Common Stock	1,376,249	$0	0	I	By Funds⁽²⁾⁽³⁾
Series B Convertible Preferred Stock	⁽¹⁾	09/24/2013		C			507,665	⁽¹⁾	⁽¹⁾	Common Stock	507,665	$0	0	I	By Funds⁽³⁾⁽⁴⁾
Series C Convertible Preferred Stock	⁽¹⁾	09/24/2013		C			293,143	⁽¹⁾	⁽¹⁾	Common Stock	293,143	$0	0	I	By Funds⁽³⁾⁽⁵⁾
Series D Convertible Preferred Stock	⁽¹⁾	09/24/2013		C			39,175	⁽¹⁾	⁽¹⁾	Common Stock	39,175	$0	0	I	By Funds⁽³⁾⁽⁶⁾
Series E Convertible Preferred Stock	⁽⁷⁾	09/24/2013		J			118,240	⁽⁷⁾	⁽⁷⁾	Common Stock	190,571	$0	0	I	By Funds⁽³⁾⁽⁸⁾
Series F Convertible Preferred Stock	⁽¹⁾	09/24/2013		C			79,617	⁽¹⁾	⁽¹⁾	Common Stock	79,617	$0	0	I	By Funds⁽³⁾⁽⁹⁾

Explanation of Responses:

1. Upon closing of the Issuer's initial public offering, each share of Series A, B, C, D and F Convertible Preferred Stock automatically converted into one share of Common Stock without payment of further consideration. The shares had no expiration date.

2. Consists of an aggregate of 1,120,746 shares of Series A Convertible Preferred Stock ("Series A Stock") held by Venrock Associates IV, L.P. ("Venrock IV"), 228,457 shares of Series A Stock held by Venrock Partners, L.P. ("Venrock Partners"), and 27,046 shares of Series A Stock held by Venrock Entrepreneurs Fund IV, L.P. ("Venrock Entrepreneurs" and together with Venrock IV and Venrock Partners, the "Venrock Entities").

3. The sole general partner of Venrock IV is Venrock Management IV, LLC ("VM4"). The sole general partner of Venrock Partners is Venrock Partners Management, LLC ("VPM"). The sole general partner of Venrock Entrepreneurs is VEF Management IV, LLC ("VEFM4"). VM4, VPM and VEFM4 disclaim beneficial ownership over all shares held by the Venrock Entities, except to the extent of their indirect pecuniary interests therein. Anthony B. Evnin is a member of VM4, VPM and VEFM4 and as such, he may be deemed to have voting and investment power with respect to these shares. Dr. Evnin disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.

4. Consists of an aggregate of 413,240 shares of Series B Convertible Preferred Stock ("Series B Stock") held by Venrock IV, 84,272 shares of Series B Stock held by Venrock Partners, and 10,153 shares of Series B Stock held by Venrock Entrepreneurs.

5. Consists of an aggregate of 238,619 shares of Series C Convertible Preferred Stock ("Series C Stock") held by Venrock IV, 48,662 shares of Series C Stock held by Venrock Partners, and 5,862 shares of Series C Stock held by Venrock Entrepreneurs.

6. Consists of an aggregate of 31,889 shares of Series D Convertible Preferred Stock ("Series D Stock") held by Venrock IV, 6,503 shares of Series D Stock held by Venrock Partners, and 783 shares of Series D Stock held by Venrock Entrepreneurs.

7. Upon closing of the Issuer's initial public offering, each share of Series E Convertible Preferred Stock ("Series E Stock") automatically converted at a ratio of 1-for-1.61174 into the number of shares of Common Stock shown in column 7 without payment of further consideration. The shares had no expiration date.

8. Consists of an aggregate of 96,248 shares of Series E Stock held by Venrock IV, 19,628 shares of Series E Stock held by Venrock Partners, and 2,364 shares of Series E Stock held by Venrock Entrepreneurs.

9. Consists of an aggregate of 64,809 shares of Series F Convertible Preferred Stock ("Series F Stock") held by Venrock IV, 13,216 shares of Series F Stock held by Venrock Partners, and 1,592 shares of Series F Stock held by Venrock Entrepreneurs.

10. Consists of an aggregate of 1,128,669 shares of Common Stock held by Venrock IV, 230,072 shares of Common Stock held by Venrock Partners, and 27,240 shares of Common Stock held by Venrock Entrepreneurs.

11. Consists of an aggregate of 1,541,909 shares of Common Stock held by Venrock IV, 314,344 shares of Common Stock held by Venrock Partners, and 37,393 shares of Common Stock held by Venrock Entrepreneurs.

12. Consists of an aggregate of 1,780,528 shares of Common Stock held by Venrock IV, 363,006 shares of Common Stock held by Venrock Partners, and 43,255 shares of Common Stock held by Venrock Entrepreneurs.

13. Consists of an aggregate of 1,812,417 shares of Common Stock held by Venrock IV, 369,509 shares of Common Stock held by Venrock Partners, and 44,038 shares of Common Stock held by Venrock Entrepreneurs.

14. Consists of an aggregate of 1,967,543 shares of Common Stock held by Venrock IV, 401,144 shares of Common Stock held by Venrock Partners, and 47,848 shares of Common Stock held by Venrock Entrepreneurs.

15. Consists of an aggregate of 2,032,352 shares of Common Stock held by Venrock IV, 414,360 shares of Common Stock held by Venrock Partners, and 49,440 shares of Common Stock held by Venrock Entrepreneurs.

Remarks:

	/s/ Anthony B. Evnin	09/26/2013
	** Signature of Reporting Person	Date
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