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^*

George Jean

(Last)

(First)

(Middle)

C/O ADVANCED TECHNOLOGY VENTURES

500 BOYLSTON STREET SUITE 1380

(Street)

BOSTON

02116

(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		1,376,248	A	⁽¹⁰⁾	1,385,980	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Common Stock	09/24/2013		C		507,664	A	⁽¹⁰⁾	1,893,644	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Common Stock	09/24/2013		C		293,142	A	⁽¹⁰⁾	2,186,786	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Common Stock	09/24/2013		C		39,172	A	⁽¹⁰⁾	2,225,958	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Common Stock	09/24/2013		J		223,806	A	⁽¹¹⁾	2,449,764	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Common Stock	09/24/2013		C		64,019	A	⁽¹⁰⁾	2,513,783	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾

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	⁽¹⁰⁾	09/24/2013		C			1,376,248	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	1,376,248	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾⁽⁹⁾
Series B Convertible Preferred Stock	⁽¹⁰⁾	09/24/2013		C			507,664	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	507,664	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾
Series C Convertible Preferred Stock	⁽¹⁰⁾	09/24/2013		C			293,142	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	293,142	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾
Series D Convertible Preferred Stock	⁽¹⁰⁾	09/24/2013		C			39,172	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	39,172	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾
Series E Convertible Preferred Stock	⁽¹¹⁾	09/24/2013		J			138,862	⁽¹¹⁾	⁽¹¹⁾	Common Stock	223,806	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾
Series F Convertible Preferred Stock	⁽¹⁰⁾	09/24/2013		C			64,019	⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	64,019	$0	0	I	See Footnote⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾

Explanation of Responses:

1. 7,831 shares of common stock, 1,103,378 shares of Series A Convertible Preferred Stock, 408,439 shares of Series B Convertible Preferred Stock, 235,847 shares of Series C Convertible Preferred Stock, 31,518 shares of Series D Convertible Preferred Stock, 111,722 shares of Series E Convertible Preferred Stock and 51,507 shares of Series F Convertible Preferred Stock of the registrant were owned directly by Advanced Technology Ventures VII, L.P. (ATV VII). After the conversions listed herein ATV VII owns 2,018,586 shares of common stock.

2. ATV Associates VII, L.L.C. (ATV A VII) is the general partner of ATV VII and exercises voting and dispositive authority over the shares held by ATV VII. Jean George is a managing director of ATV A VII and exercises voting and dispositive decisions of ATV A VII collectively with each of four other managing directors. ATV A VII and each of the managing directors disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein.

3. 314 shares of common stock, 44,278 shares of Series A Convertible Preferred Stock, 16,390 shares of Series B Convertible Preferred Stock, 9,464 shares of Series C Convertible Preferred Stock, 1,264 shares of Series D Convertible Preferred Stock, 4,483 shares of Series E Convertible Preferred Stock and 2,067 shares of Series F Convertible Preferred Stock of the registrant were owned directly by Advanced Technology Ventures VII (B), L.P. (ATV VII B). After the conversions listed herein ATV VII B owns 81,002 shares of common stock.

4. ATV A VII is the general partner of ATV VII B and exercises voting and dispositive authority over the shares held by ATV VII B. ATV A VII and each of the managing directors disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein.

5. 151 shares of common stock, 21,283 shares of Series A Convertible Preferred Stock, 7,878 shares of Series B Convertible Preferred Stock, 4,549 shares of Series C Convertible Preferred Stock, 607 shares of Series D Convertible Preferred Stock, 2,155 shares of Series E Convertible Preferred Stock and 993 shares of Series F Convertible Preferred Stock of the registrant were owned directly by Advanced Technology Ventures VII (C), L.P. (ATV VII C). ATV A VII is the general partner of ATV VII C and exercises voting and authority decisions over the shares held by ATV VII C. ATV A VII and each of the managing directors including Ms. George disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein. After the conversions listed herein ATV VII C owns 38,934 shares of common stock.

6. 46 shares of common stock, 6,575 shares of Series A Convertible Preferred Stock, 2,434 shares of Series B Convertible Preferred Stock, 1,405 shares of Series C Convertible Preferred Stock, 187 shares of Series D Convertible Preferred Stock, 665 shares of Series E Convertible Preferred Stock and 307 shares of Series F Convertible Preferred Stock of the registrant were owned directly by ATV Entrepreneurs VII, L.P. (ATV VII E). ATV A VII is the general partner of ATV VII E and exercises voting and dispositive authority over the shares held by ATV VII E. ATV A VII and each of the managing directors including Ms. George disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein. After the conversions listed herein ATV VII E owns 12,025 shares of common stock.

7. 1,307 shares of common stock, 184,810 shares of Series A Convertible Preferred Stock, 68,172 shares of Series B Convertible Preferred Stock, 39,365 shares of Series C Convertible Preferred Stock, 5,260 shares of Series D Convertible Preferred Stock, 18,647 shares of Series E Convertible Preferred Stock and 8,597 shares of Series F Convertible Preferred Stock of the registrant were owned directly by Advanced Technology Ventures VI, L.P. (ATV VI). ATV Associates VI, L.L.C. (ATV A VI) is the general partner of ATV VI and exercises voting and dispositive authority over the shares held by ATV VI. ATV A VI and each of the managing directors disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein. After the conversions listed herein ATV VII E owns 337,565 shares of common stock.

8. 83 shares of common stock, 11,796 shares of Series A Convertible Preferred Stock, 4,351 shares of Series B Convertible Preferred Stock, 2,512 shares of Series C Convertible Preferred Stock, 336 shares of Series D Convertible Preferred Stock, 1,190 shares of Series E Convertible Preferred Stock and 548 shares of Series F Convertible Preferred Stock of the registrant were owned directly by ATV Entrepreneurs VI, L.P. (ATV VI E). ATV A VI is the general partner of ATV VI E and exercises voting and dispositive decisions over the shares held by ATV VI E. ATV A VI and each of the managing directors disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein. After the conversions listed herein ATV VII E owns 21,543 shares of common stock.

9. 4,128 shares of Series A Convertible Preferred Stock of the registrant weer owned directly by ATV Alliance 2003, L.P. (ATV 2003). ATV Alliance Associates, L.L.C. (ATV Alliance LLC) is the general partner of ATV 2003 and exercises voting and dispositive authority over the shares held by ATV 2003. Voting and dispositive decisions of ATV Alliance LLC are made by Ms. George. ATV Alliance LLC and George disclaim beneficial ownership of these securities and this report shall not be deemed an admission that they are the beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein. After the conversions listed herein ATV VII E owns 4,128 shares of common stock.

10. Upon closing of the Issuers 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.

11. Upon closing of the Issuers initial public offering, each share of Series E Preferred 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.

	/s/ Kevin F. McLaughlin, attorney in fact for Jean M. George	09/26/2013
	** Signature of Reporting Person	Date
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