Amphenol Corp — Additional Proxy Materials (DEFA14A)

Step 1: Go to www.envisionreports.com/APH. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. www.envisionreports.com/APH Online Go to www.envisionreports.com/APH or scan the QR code — login details are located in the shaded bar below. Stockholder Meeting Notice 048SAD Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders of Amphenol Corporation to be Held on May 21, 2026 Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual meeting of stockholders are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy of the proxy materials. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. Amphenol’s Annual Report for the fiscal year ended December 31, 2025 and 2026 Proxy Statement are available at: Obtaining a Copy of the Proxy Materials – If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before May 11, 2026 to facilitate timely delivery. 2NOT Easy Online Access — View your proxy materials and vote. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5: Vote your shares. Votes submitted electronically must be received by 11:59 p.m., Eastern Time, on May 20, 2026.

Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — Internet – Go to www.envisionreports.com/APH. Click Cast Your Vote or Request Materials. — Phone – Call us free of charge at 1-866-641-4276. — Email – Send an email to investorvote@computershare.com with “Proxy Materials Amphenol Corporation” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by May 11, 2026. The Annual Meeting of Stockholders of Amphenol Corporation will be held on May 21, 2026 at its World Headquarters at 358 Hall Avenue, Wallingford, Connecticut 06492, at 11:00 a.m., Eastern Time. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends a vote FOR each of the nominees listed and FOR Proposals 2 and 3: 1. Election of Eight Directors: 01 - Nancy A. Altobello 02 - David P. Falck 03 - Sanjiv Lamba 04 - Rita S. Lane 05 - Robert A. Livingston 06 - R. Adam Norwitt 07 - Prahlad Singh 08 - Anne Clarke Wolff 2. Ratification of the selection of Deloitte & Touche LLP as independent public accountants 3. Advisory vote to approve compensation of named executive officers PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online, call 1-800-652-8683 or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you. For directions to the meeting and instructions on voting in person, please call 203-265-8627. Stockholder Meeting Notice