SEC FORM 3

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^*

EVNIN ANTHONY B

(Last)

(First)

(Middle)

C/O VENROCK

530 FIFTH AVENUE, 22ND FLOOR

(Street)

NEW YORK

10036

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
09/18/2013

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

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

X	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)

X	Form filed by One Reporting Person
	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)
Common Stock	9,732	I	By Funds⁽¹⁾⁽²⁾

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)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	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)
Series A Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	1,376,249	⁽³⁾	I	By Funds⁽²⁾⁽⁴⁾
Series B Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	507,665	⁽³⁾	I	By Funds⁽²⁾⁽⁵⁾
Series C Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	293,143	⁽³⁾	I	By Funds⁽²⁾⁽⁶⁾
Series D Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	39,175	⁽³⁾	I	By Funds⁽²⁾⁽⁷⁾
Series E Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	190,571	⁽³⁾	I	By Funds⁽²⁾⁽⁸⁾
Series F Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	79,617	⁽³⁾	I	By Funds⁽²⁾⁽⁹⁾
Warrants to Purchase Common Stock	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	126,283	$5.88	I	By Funds⁽²⁾⁽¹¹⁾

Explanation of Responses:

1. Consists of an aggregate of 7,923 shares of Common Stock held by Venrock Associates IV, L.P. ("Venrock IV"), 1,615 shares of Common Stock held by Venrock Partners, L.P. ("Venrock Partners"), and 194 shares of Common Stock held by Venrock Entrepreneurs Fund IV, L.P. ("Venrock Entrepreneurs" and together with Venrock IV and Venrock Partners, the "Venrock Entities").

2. 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.

3. The Series A Convertible Preferred Stock, Series B Convertible Preferred Stock, Series C Convertible Preferred Stock, Series D Convertible Preferred Stock, Series E Convertible Preferred Stock and Series F Convertible Preferred Stock are each convertible into Common Stock at any time at the holder's election and upon the consummation of a qualified public offering of the registrant. There is no expiration date for any series of convertible preferred stock.

4. Consists of an aggregate of 1,120,746 shares of Series A Convertible Preferred Stock ("Series A Stock") held by Venrock IV, 228,457 shares of Series A Stock held by Venrock Partners, and 27,046 shares of Series A Stock held by Venrock Entrepreneurs.

5. 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.

6. 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.

7. 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.

8. Consists of an aggregate of 155,126 shares of Series E Convertible Preferred Stock ("Series E Stock") held by Venrock IV, 31,635 shares of Series E Stock held by Venrock Partners, and 3,810 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. The warrants to purchase Common Stock are exercisable at any time at the holder's election and have an expiration date on the ten year anniversary of the warrant issue date.

11. Consists of an aggregate of 102,795 warrants to purchase Common Stock held by Venrock IV, 20,963 warrants to purchase Common Stock held by Venrock Partners, and 2,525 warrants to purchase Common Stock held by Venrock Entrepreneurs.

Remarks:

	/s/ Anthony B. Evnin	09/18/2013
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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