You invested in QUANTUM-SI INCORPORATED and it's time to vote! You have the
right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the shareholder meeting to be held on May 15, 2024. Get informed before you vote View the 10K
and Proxy Statement online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 25, 2024. If you would like to request a copy of the material(s) for this and/or future shareholder meetings, you may
(1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not
otherwise receive a paper or email copy. *If you choose to vote these shares in person at the meeting, you must request a “legal proxy.” To do so, please follow the instructions at www.ProxyVote.com or request a paper copy of the
materials, which will contain the appropriate instructions. Please check the meeting materials for any special requirements for meeting attendance. Smartphone users Point your camera here and vote without entering a control number Your
Vote Counts! FLASHID-JOB# For complete information and to vote, visit www.ProxyVote.com Control # Ricky Campana P.O. Box 123456 Suite 500 51 Mercedes Way Edgewood, NY 11717 1 OF 322,224 148,294 2 30# Hextone, Inc. P.O. Box
9142 Farmingdale, NY 11735 XXXX XXXX XXXX XXXX QUANTUM-SI INCORPORATED 2024 Annual Meeting Vote by May 14, 2024 11:59 PM ET Vote in Person at the Meeting* May 15, 2024 12:00 PM EST Virtually at: https://www.iproxydirect.com/QSI