Jay T. Backstrom Form 4 ACCELERON PHARMA / Jay T. Backstrom 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

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X

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^*

Backstrom Jay T.

(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)
EVP, Research and Development

3. Date of Earliest Transaction (Month/Day/Year)
11/19/2021

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	11/19/2021		U(1)		21,233(1)	D	(1)	0	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	$52.61	11/19/2021		D			96,963	(2)	(2)	Common Stock	96,963	(2)	0	D
Option to Purchase Common Stock	$115.53	11/19/2021		D			20,896	(2)	(2)	Common Stock	20,896	(2)	0	D

Explanation of Responses:

1. This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

2. Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

	/s/ Adam M. Veness, as attorney-in-fact for Jay T. Backstrom	11/22/2021
	** 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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