KEVIN F. MCLAUGHLIN - 19 Nov 2021 Form 4 Insider Report for ACCELERON PHARMA INC (XLRN)

Role: SVP, CFO and Treasurer
Signature: /s/ Adam M. Veness, as attorney-in-fact for Kevin F. McLaughlin
Issuer symbol: XLRN
Transactions as of: 19 Nov 2021
Net transactions value: $0
Form type: 4
Filing time: 22 Nov 2021, 08:03:19 UTC
Previous filing: 24 Sep 2021
Next filing: 29 Apr 2022
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	XLRN	Common Stock	Disposition pursuant to a tender of shares in a change of control transaction		-10,681	-100%		0	19 Nov 2021	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Shares	Change %	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	XLRN	Option to Purchase Common Stock	Disposed to Issuer	-2,663	-100%	19 Nov 2021	Common Stock	2,663	$30.17	Direct	F2
transaction	XLRN	Option to Purchase Common Stock	Disposed to Issuer	-11,262	-100%	19 Nov 2021	Common Stock	11,262	$40.61	Direct	F2
transaction	XLRN	Option to Purchase Common Stock	Disposed to Issuer	-20,500	-100%	19 Nov 2021	Common Stock	20,500	$41.64	Direct	F2
transaction	XLRN	Option to Purchase Common Stock	Disposed to Issuer	-24,334	-100%	19 Nov 2021	Common Stock	24,334	$52.99	Direct	F2
transaction	XLRN	Option to Purchase Common Stock	Disposed to Issuer	-18,806	-100%	19 Nov 2021	Common Stock	18,806	$115.53	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

KEVIN F. MCLAUGHLIN is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id	Content
F1	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.
F2	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.

Content

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.

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.