Alkermes plc. — Director's Dealing 2014

May 30, 2014

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alkermes plc. (ALKS)
CIK: 0001520262
Period of Report: 2014-05-28

Reporting Person: Peterson Rebecca (SVP, Corporate Communications)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2014-05-28	Ordinary Shares	M	20000	$33.72	Acquired	20000	Direct
2014-05-28	Ordinary Shares	S	17800	$45.7855	Disposed	2200	Direct
2014-05-28	Ordinary Shares	S	2200	$46.4673	Disposed	0	Direct
2014-05-28	Ordinary Shares	M	3750	—	Acquired	3750	Direct
2014-05-28	Ordinary Shares	F	1769	$45.74	Disposed	1981	Direct
2014-05-30	Ordinary Shares	S	1981	$45.87	Disposed	0	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2014-05-28	Employee Stock Option (Right to Buy)	$33.72	M	20000	Disposed	2023-05-28	Ordinary Shares (20000)	Direct
2014-05-28	Restricted Stock Unit Award	$0	M	3750	Disposed		Ordinary Shares (3750)	Direct

Footnotes

F1: This option exercise was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F2: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F3: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.39 to $46.32. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

F4: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $46.40 to $46.56. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

F5: Shares subject to the stock option award vest in four equal annual installments commencing on 5/28/14.

F6: Shares subject to the restricted stock unit award vest in equal annual installments over a four year period, commencing on 5/28/14.