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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	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 VENTURE 500 BOYLSTON STREET, SUITE 1380 (Street) BOSTON MA 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) 06/26/2019
	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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/26/2019		M		20,000	A	$24.11	23,750	D
Common Stock	06/26/2019		M		10,000	A	$27.97	33,750	D
Common Stock	06/26/2019		M		7,500	A	$30.17	41,250	D
Common Stock	06/26/2019		S(1)		25,688	D	$39.16(2)	15,562	D
Common Stock	06/26/2019		J(3)		11,812	D	$0.00	3,750	D
Common Stock	06/26/2019		J(3)		11,812	A	$0.00	11,812	I	See Footnote(4)
Common Stock	06/28/2019		S		11,812	D	$41.17(5)	0	I	See Footnote(4)

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Option to Purchase Common Stock	$24.11	06/26/2019		M			20,000	(6)	12/05/2023	Common Stock	20,000	$0.00	0	D(3)
Option to Purchase Common Stock	$27.97	06/26/2019		M			10,000	(7)	03/03/2026	Common Stock	10,000	$0.00	0	D(3)
Option to Purchase Common Stock	$30.17	06/26/2019		M			7,500	(7)	03/02/2027	Common Stock	7,500	$0.00	0	D(3)

Explanation of Responses:

1. These shares were sold to cover the exercise price of the three options reported herein.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.00 to $39.51, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (2) and (5) to this Form 4.

3. The Reporting Person held the options and underlying shares for the benefit of ATV Capital Management, Inc. ("ACM") pursuant to ACM's policy with respect to equity compensation in respect of director service. Pursuant to the policy, the Reporting Person assigned these shares to ACM for no additional consideration.

4. These securities are directly owned by ACM. The Reporting Person is a director of ACM. The Reporting Person disclaims beneficial ownership of these securities and this report shall not be deemed an admission that she is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of her pecuniary interest therein.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from 40.93 to 41.37, inclusive.

6. The shares of common stock underlying this stock option award vested in equal quarterly installments over the first three years after the grant.

7. The shares of common stock underlying this stock option award vested in full on the one year anniversary of the grant date.

Remarks:

	/s/ Jean George	06/28/2019
	** 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 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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