Alkermes plc.

During the three months ended June 30, 2026, the following contracts, instructions or written plans for the purchase or sale of the Company’s securities that are or were intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act (each, a “Rule 10b5-1 plan”) were adopted by officers (as defined in Rule 16a-1(f) under the Exchange Act) and directors of the Company: (i) on May 15, 2026, Christian Todd Nichols, our Chief Commercial Officer, adopted a Rule 10b5-1 plan providing for the sale of up to 7,576 ordinary shares of the Company; this plan is scheduled to expire on February 10, 2027; (ii) on June 8, 2026, Samuel Parisi, our Interim Principal Accounting Officer, adopted a Rule 10b5-1 plan providing for the sale of up to 27,785 ordinary shares of the Company that may be obtained from the exercise of vested stock options or the vesting of restricted stock unit awards; this plan is scheduled to expire on September 7, 2027; and (iii) on June 12, 2026, Blair Jackson, our Chief Operating Officer, adopted a Rule 10b5-1 plan providing for the sale of up to 35,699 ordinary shares of the Company that may be obtained from the exercise of vested and expiring stock options; this plan is scheduled to expire on February 17, 2027. During the three months ended June 30, 2026, no other directors or officers of the Company adopted or terminated a Rule 10b5-1 plan or a trading plan not intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.