Sec Form 4 Filing - POPS RICHARD F @ Alkermes plc. - 2024-02-26

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person POPS RICHARD F 2. Issuer Name and Ticker or Trading Symbol Alkermes plc. [ ALKS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Director and CEO, Alkermes plc (Last) (First) (Middle) CONNAUGHT HOUSE, 1 BURLINGTON ROAD 3. Date of Earliest Transaction (MM/DD/YY) 02/26/2024 (Street) DUBLIN 4 IRELAND 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Employee Stock Option (Right to Buy) ( 1 ) $ 46.24 11/17/2023 J V 4,599 ( 2 ) 03/03/2024 Ordinary Shares 4,599 $ 46.24 234,599 D Employee Stock Option (Right to Buy) ( 1 ) $ 69.83 11/17/2023 J V 3,999 ( 2 ) 02/26/2025 Ordinary Shares 3,999 $ 69.83 203,999 D Employee Stock Option (Right to Buy) ( 1 ) $ 31.64 11/17/2023 J V 5,999 ( 2 ) 02/28/2026 Ordinary Shares 5,999 $ 31.64 305,999 D Employee Stock Option (Right to Buy) ( 1 ) $ 53.5 11/17/2023 J V 3,999 ( 2 ) 02/17/2027 Ordinary Shares 3,999 $ 53.5 203,999 D Employee Stock Option (Right to Buy) ( 1 ) $ 65.94 11/17/2023 J V 5,899 ( 2 ) 02/16/2028 Ordinary Shares 5,899 $ 65.94 300,899 D Employee Stock Option (Right to Buy) ( 1 ) $ 31.93 11/17/2023 J V 2,419 ( 2 ) 02/21/2029 Ordinary Shares 2,419 $ 31.93 123,419 D Employee Stock Option (Right to Buy) ( 1 ) $ 31.93 11/17/2023 J V 7,644 ( 3 ) 02/21/2029 Ordinary Shares 7,644 $ 31.93 389,844 D Employee Stock Option (Right to Buy) ( 1 ) $ 20.03 11/17/2023 J V 7,168 ( 4 ) 02/20/2030 Ordinary Shares 7,168 $ 20.03 365,634 D Employee Stock Option (Right to Buy) ( 1 ) $ 19.34 11/17/2023 J V 6,843 ( 5 ) 02/22/2031 Ordinary Shares 6,843 $ 19.34 349,030 D Employee Stock Option (Right to Buy) ( 1 ) $ 24.59 11/17/2023 J V 5,980 ( 6 ) 02/18/2032 Ordinary Shares 5,980 $ 24.59 305,024 D Employee Stock Option (Right to Buy) ( 1 ) $ 26.82 11/17/2023 J V 5,697 ( 7 ) 02/23/2033 Ordinary Shares 5,697 $ 26.82 290,570 D Employee Stock Option (Right to Buy) $ 30.04 02/26/2024 A 274,328 ( 8 ) 02/26/2034 Ordinary Shares 274,328 $ 0 274,328 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other POPS RICHARD F CONNAUGHT HOUSE 1 BURLINGTON ROAD DUBLIN 4 IRELAND X Director and CEO, Alkermes plc Signatures /s/ Jeffrey Geary, attorney-in-fact for Richard F. Pops 02/27/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents an equity award granted prior to the separation of the issuer's oncology business into Mural Oncology plc (the "Separation"), as adjusted on November 17, 2023 in connection with the Separation (in order to preserve the value associated with the original award) based on the equity adjustment terms set forth in the Employee Matters Agreement filed by the issuer as Exhibit 10.2 to its Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission on November 15, 2023. The exercise price (if any) of the adjusted award is shown in Boxes 2 and 8, the number of shares subject to the adjusted award is shown in Box 9 and the number of shares added to the award pursuant to the adjustment is shown in Box 5. ( 2 )These options are fully vested in accordance with their terms. ( 3 )Shares underlying the stock option award shall not vest and become exercisable unless and until the closing price of an ordinary share of Alkermes plc, as reported by the Nasdaq Global Select Market or another national securities exchange on which Alkermes plc's ordinary shares are listed, is fifty U.S. Dollars (US$50.00) or higher for thirty (30) consecutive trading days during the term of the award (the "performance criteria"). Subject to achievement of the performance criteria, the shares underlying the stock option award shall vest in four equal annual installments commencing on 2/21/2020. This award expires ten years from the date of grant. ( 4 )Shares subject to the stock option award vest and become exercisable in four equal annual installments commencing on 2/20/2021. ( 5 )Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/22/2022. ( 6 )Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/18/2023. ( 7 )Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/23/2024. ( 8 )Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/26/2025.

Remarks: EXHIBIT LIST: Exhibit 24.1 - Power of Attorney

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