Mclaughlin Kevin F Form 4 ACCELERON PHARMA / KEVIN F MCLAUGHLIN ownership change

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^*

MCLAUGHLIN KEVIN F

(Last) (First) (Middle)

128 SIDNEY STREET

(Street)

CAMBRIDGE MA 02139

(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)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
SVP, CFO and Treasurer

3. Date of Earliest Transaction (Month/Day/Year)
12/09/2020

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	12/09/2020		M(1)		548	A	$41.2	11,764	D
Common Stock	12/09/2020		M(1)		400	A	$27.97	12,164	D
Common Stock	12/09/2020		M(1)		1,051	A	$30.17	13,215	D
Common Stock	12/09/2020		M(1)		1,873	A	$40.61	15,088	D
Common Stock	12/09/2020		S(1)		3,872	D	$125.03(2)	11,216	D
Common Stock	12/10/2020		M(1)		100	A	$41.2	11,316	D
Common Stock	12/10/2020		M(1)		200	A	$27.97	11,516	D
Common Stock	12/10/2020		M(1)		100	A	$30.17	11,616	D
Common Stock	12/10/2020		M(1)		100	A	$40.61	11,716	D
Common Stock	12/10/2020		S(1)		500	D	$125.12	11,216	D
Common Stock	12/11/2020		M(1)		3,100	A	$41.2	14,316	D
Common Stock	12/11/2020		S(1)		3,100	D	$125	11,216	D

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	$41.2	12/09/2020		M(1)			548	(3)	01/08/2025	Common Stock	548	$0	10,452	D
Option to Purchase Common Stock	$27.97	12/09/2020		M(1)			400	(4)	03/03/2026	Common Stock	400	$0	7,900	D
Option to Purchase Common Stock	$30.17	12/09/2020		M(1)			1,051	(5)	03/02/2027	Common Stock	1,051	$0	30,249	D
Option to Purchase Common Stock	$40.61	12/09/2020		M(1)			1,873	(6)	03/01/2028	Common Stock	1,873	$0	28,952	D
Option to Purchase Common Stock	$41.2	12/10/2020		M(1)			100	(3)	01/08/2025	Common Stock	100	$0	10,352	D
Option to Purchase Common Stock	$27.97	12/10/2020		M(1)			200	(4)	03/03/2026	Common Stock	200	$0	7,700	D
Option to Purchase Common Stock	$30.17	12/10/2020		M(1)			100	(5)	03/02/2027	Common Stock	100	$0	30,149	D
Option to Purchase Common Stock	$40.61	12/10/2020		M(1)			100	(6)	03/01/2028	Common Stock	100	$0	28,852	D
Option to Purchase Common Stock	$41.2	12/11/2020		M(1)			3,100	(3)	01/08/2025	Common Stock	3,100	$0	7,252	D

Explanation of Responses:

1. The reported transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $125.00 to $125.27 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

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

4. The shares of common stock underlying this stock option award vested in equal quarterly installments over the four years after January 1, 2016.

5. The shares of common stock underlying this stock option award vest in equal quarterly installments over the four years after January 1, 2017.

6. The shares of common stock underlying this stock option award vest in equal quarterly installments over the four years after January 1, 2018.

	/s/ Adam M. Veness, as attorney-in-fact for Kevin F. McLaughlin	12/11/2020
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.