ALLEGRO MICROSYSTEMS INC

This proxy statement is furnished in connection with the solicitation by the Board of Directors (the “Board”) of Allegro MicroSystems, Inc. (“we,” “us,” “our,” the “Company” or “Allegro”) of proxies to be voted at our Annual Meeting of Shareholders to be held on Thursday, August 7, 2025 (the “Annual Meeting”), at 8:30 a.m. Eastern time, and at any continuation, postponement, or adjournment of the Annual Meeting. In order to provide accessibility to the meeting to all shareholders, the Annual Meeting will be a completely virtual meeting conducted via live, online webcast. You will be able to attend and participate in the Annual Meeting online, vote your shares electronically and submit your questions during the Annual Meeting by visiting: meetnow.global/MYMVHCL at the meeting date and time. In order to attend, if you hold your shares through an intermediary, such as a bank, broker, or other nominee, you must register in advance prior to the deadline of 5:00 p.m. Eastern time on August 4, 2025. Please refer to “How can I attend the Annual Meeting?” for information on how to register. There is no physical location for the Annual Meeting.

Holders of record of our outstanding shares of common stock, $0.01 par value per share (“Common Stock”), as of the close of business on June 11, 2025 (the “Record Date”), will be entitled to notice of and to vote at the Annual Meeting and any continuation, postponement, or adjournment of the Annual Meeting, and will vote as a single class on all matters presented at the Annual Meeting. As of the Record Date, there were 184,925,395 shares of Common Stock outstanding and entitled to vote at the Annual Meeting. Each share of Common Stock is entitled to one vote on any matter presented to shareholders at the Annual Meeting.

This proxy statement and the Company’s Annual Report to Shareholders for the fiscal year ended March 28, 2025 (the “2025 Annual Report”) will be released on or about June 25, 2025 to our shareholders as of the Record Date.

Information contained on, or that can be accessed through, our website is not incorporated by reference in this proxy statement and does not form a part of this proxy statement. The inclusion of links and website addresses in this proxy statement are textual references only. Moreover, certain disclosures in this proxy statement—including relating to our aspirations, goals and any statements other than historical fact—are intended to be forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements are subject to varying risks and uncertainties, including risks and uncertainties relating to alignment with stakeholder expectations, which may cause ultimate results to differ materially. However, our discussion of various items (including environmental, social and governance ("ESG") information) herein or elsewhere is informed by the interests of various frameworks and stakeholders, and such information may not necessarily be material for purposes of our U.S. securities filings or other regulatory purposes. Our approach to such matters may evolve, particularly as standards, methodologies and expectations change, but also for other reasons which may be out of our control.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE SHAREHOLDER MEETING TO BE HELD ON AUGUST 7, 2025

This proxy statement and our 2025 Annual Report are available atinvestors.allegromicro.com/financials/annual-reports.

Proposals

At the Annual Meeting, our shareholders will be asked:

We do not know of any other business that will be presented at the Annual Meeting. However, if any other matter properly comes before the shareholders for a vote at the Annual Meeting, the proxy holders named on the Company’s proxy card will have the discretionary authority to vote your shares in accordance with their best judgment.

PROXY STATEMENT SUMMARY

Recommendations of the Board

The Board recommends that you vote your shares as indicated below. If you return a properly completed proxy card, or vote your shares by telephone or Internet, your shares of Common Stock will be voted on your behalf as you direct. If not otherwise specified, the shares of Common Stock represented by the proxies will be voted, and the Board recommends that you vote:

a.

FOR the election of each of Michael C. Doogue, Katsumi Kawashima and Yoshihiro (Zen) Suzuki as Class II Directors to serve until the 2028 Annual Meeting of Shareholders;

b.

FOR the ratification of the appointment of PwC as the Company's independent registered public accounting firm for the fiscal year ending March 27, 2026; and

c.

FOR the approval, on an advisory basis, of the Company’s executive compensation.

If any other matter properly comes before the shareholders for a vote at the Annual Meeting, the proxy holders named on the Company’s proxy card will have the discretionary authority to vote your shares in accordance with their best judgment.

Information About This Proxy Statement

Why You Received this Proxy Statement. You have received these proxy materials because the Board is soliciting your proxy to vote your shares at the Annual Meeting. This proxy statement includes information that we are required to provide to you under the rules of the Securities and Exchange Commission (“SEC”) and that is designed to assist you in voting your shares.

Notice of Internet Availability of Proxy Materials. As permitted by SEC rules, we are making this proxy statement and our 2025 Annual Report available to our shareholders electronically via the Internet. On or about June 25, 2025, we mailed to our shareholders a Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access this proxy statement and our 2025 Annual Report and vote online. If you received a Notice by mail, you will not receive a printed copy of the proxy materials in the mail unless you specifically request them. Instead, the Notice instructs you on how to access and review all of the important information contained in the proxy statement and 2025 Annual Report. The Notice also instructs you on how you may submit your proxy over the Internet. If you received a Notice by mail and would like to receive a printed copy of our proxy materials, you should follow the instructions for requesting such materials contained on the Notice.

Printed Copies of Our Proxy Materials. If you received printed copies of our proxy materials, then instructions regarding how you can vote are contained on the proxy card or voting instruction form included in the materials.

Householding. The SEC’s rules permit us to deliver a single set of proxy materials to one address shared by two or more of our shareholders. This delivery method is referred to as “householding” and can result in significant cost savings. To take advantage of this opportunity, we have delivered a single copy of the 2025 Annual Report, proxy statement or Notice, as applicable, to multiple shareholders who share an address, unless we received contrary instructions prior to the mailing date. We agree to deliver promptly, upon written or oral request, a separate copy of the 2025 Annual Report, proxy statement or Notice, as requested, to any shareholder at the shared address to which a single copy of those documents was delivered. If you prefer to receive separate copies of the 2025 Annual Report, proxy statement or Notice, or separate copies of proxy materials in the future, contact our transfer agent at (800) 736-3001 or write them at Computershare, P.O. Box 43006, Providence, RI 02940-3006.

If you are currently a shareholder sharing an address with another shareholder receiving multiple copies and wish to receive only one copy of future proxy materials for your household, please contact Computershare at the above phone number or address.