Sec Form 4/A Filing - MCGUIRE TERRANCE @ ACCELERON PHARMA INC - 2015-08-17

Insider filing report for Changes in Beneficial Ownership
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FORM 4/A
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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1. Name and Address of Reporting Person
MCGUIRE TERRANCE
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)
(Last) (First) (Middle)
C/O POLARIS VENTURE PARTNERS, 1000 WINTER STREET
3. Date of Earliest Transaction (MM/DD/YY)
08/17/2015
(Street)
WALTHAM, MA02451
4. If Amendment, Date Original Filed (MM/DD/YY)
08/19/2015
6. Individual or Joint/Group Filing (Check Applicable Line)
__ X __ Form filed by One Reporting Person
_____ Form filed by More than One Reporting Person
(City) (State) (Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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)
Code V Amount (A) or (D) Price
Common Stock 08/17/2015 S 407,259 ( 1 ) D $ 30.25 1,298,153 ( 2 ) ( 3 ) ( 4 ) I See Footnotes ( 2 ) ( 3 )
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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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
(MM/DD/YY)
7. Title and Amount of Underlying Securities
(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 of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Reporting Owners
Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
MCGUIRE TERRANCE
C/O POLARIS VENTURE PARTNERS
1000 WINTER STREET
WALTHAM, MA02451
X
Signatures
/s/ Terrance McGuire 08/26/2015
Signature of Reporting Person Date
Explanation of Responses:
( 1 )Represents 400,000 shares sold by Polaris Venture Partners IV, L.P. ("PVP IV") and 7,259 shares sold by Polaris Venture Partners Entrepreneurs' Fund IV, L.P. ("PVPE IV" and, together with PVP IV, the "Funds").
( 2 )The Reporting Person is a director of the Issuer and managing member of Polaris Venture Management Co. IV, L.L.C. ("PVM IV"), the general partner of each of PVP IV and PVPE IV. The amount of securities beneficially owned as reported in column 5 represents 1,273,175 shares, 22,983 shares, and 1,995 shares that are held directly by PVP IV, PVPE IV and PVM IV, respectively following the transactions reported in this Form 4. PVM IV disclaims beneficial ownership of the Funds' securities and this report shall not be deemed an admission that PVM IV is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of its pecuniary interest, if any, therein. (Continued in Footnote 3)
( 3 )Each of Jonathan A. Flint and the Reporting Person are the managing members of PVM IV and each of them disclaims beneficial ownership of the Funds' and PVM IV's securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest, if any, therein.
( 4 )The initial Form 4 filed on August 19, 2015 by the Reporting Person inadvertently listed the incorrect number of shares beneficially owned following the reported transaction in column 5 and with regard to PMV IV in Footnote 2.

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 4(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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