Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934

¨     Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨     Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

Step 1: Go to www.envisionreports.com/sens. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. www.edocumentview.com/sens Online Go to www.envisionreports.com/sens or scan the QR code — login details are located in the shaded bar below. Senseonics Holdings, Inc. 2024 Stockholder Meeting Notice 03Z9WB + + Important Notice Regarding the Availability of Proxy Materials for the Senseonics Holdings, Inc. Stockholder Meeting to be Held on May 22, 2024 Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual stockholders’ meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. 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. The 2024 proxy statement and annual report to shareholders 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 10, 2024 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. MMMMMMMMMMMM MMMMMMMMM MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 ENDORSEMENT_LINE______________ SACKPACK_____________ 1234 5678 9012 345 C 1234567890 COY MMMMMMM 000001

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/sens. 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 The Senseonics Holdings, Inc.” 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 10, 2024. The 2024 Annual Meeting of Stockholders of The Senseonics Holdings, Inc. will be held on Wednesday, May 22, 2024 at 10:00 A.M. local time, virtually via the internet at meetnow.global/MZZTTZF. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommend a vote FOR all the nominees listed and FOR Proposals 2, 3 and 4: 1. Election of three directors: 01 – Steven Edelman M.D. 02 – Edward J. Fiorentino 03 – Anthony Raab 2. Approval, on an advisory basis, of the compensation of our named executive officers, as disclosed in this proxy statement. 3. Ratification of selection by the Audit Committee of the Board of Directors of KPMG LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2024. 4. Amend Company’s Certificate of Incorporation to increase authorized shares of common stock from 900,000,000 to 1,400,000,000. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. Stockholder Meeting Notice