ALGM: Leadership change · Company disclosure

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On May 11, 2026 and May 13, 2026, Susan D. Lynch and Richard R. Lury, respectively, each notified the Board of Directors (the “Board”) of Allegro MicroSystems, Inc. (the “Company”) of their decision to not stand for reelection as a Class III member of the Board at the Company’s 2026 Annual Meeting of Stockholders to be held on August 5, 2026 (the “Annual Meeting”). Each of Mr. Lury’s and Ms. Lynch’s service as a member of the Board shall terminate effective immediately prior to the Annual Meeting. Neither Mr. Lury’s nor Ms. Lynch’s decision to not stand for reelection is the result of any disagreement between such director and the Company or its management on any matter relating to the Company’s operations, policies or practices. On May 13, 2026, at the recommendation of the Board’s Nominating and Governance Committee and in accordance with the Second Amended and Restated Stockholders Agreement, dated as of July 29, 2024, by and among the Company, and Sanken Electric Co., Ltd., the Board took the following actions, each of which was effective May 13, 2026: (i) expanded the size of the Board to ten, (ii) elected Robert J. Willett to the Board as a Class III Director, to serve until the Annual Meeting and until his successor is duly elected and qualified, and (iii) appointed Mr. Willett to serve on the Board’s Audit Committee and Compensation Committee. The Board has determined that Mr. Willett qualifies as an independent director pursuant to the rules of The Nasdaq Stock Market. The Board has also determined that Mr. Willett meets the enhanced independence requirements for audit committee members under Rule 10A-3 of