Form DEFA14A CoastalSouth Bancshares,

Online Go to www.investorvote.com/COSO or scan the QR code — login details are located in the shaded bar below.Votes submitted electronically must be received by April 23, 2026 at 8:00 A.M., ET.Important Notice Regarding the Availability of Proxy Materials for the CoastalSouth Bancshares, Inc. Shareholder Meeting to be Held on April 23, 2026Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual shareholders’ 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 Proxy Statement, 2025 Annual Report, and Letter to Shareholders are available at: www.investorvote.com/COSO Easy Online Access — View your proxy materials and vote.Step 1: Go to www.investorvote.com/COSO. Step2: Click on the icon on the right to view meeting materials. Step 3:Return to the investorvote.com window and follow the instructions on the screen to log in. Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5:Vote your shares.When you go online, you can also help the environment by consenting to receive electronic delivery of future materials.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 April 13, 2026 to facilitate timely delivery.

CoastalSouth Bancshares, Inc.’s Annual Meeting of Shareholders will be held on April 23, 2026 at CoastalSouth Bancshares, Inc., 400 Galleria Pkwy, Suite 1900, Atlanta, GA 30339, at 8:00 A.M. ET. 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 Proposal 2:Election of Directors: John G. Aldrid L. Scott Askins Ernst W. Bruderer J. Simon FraserPatrick M. Frawley Mark A. Griffith Michael B. High James S. MacLeod James N. Richardson, Jr. Stephen R. Stone Joseph V. Topper, Jr.To ratify the appointment of Elliott Davis, LLC as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026.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. If you wish to attend and vote at the meeting, please bring this notice with you.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.investorvote.com/COSO. Phone – Call us free of charge at 1-866-641-4276.Email – Send an email to [email protected] with “Proxy Materials CoastalSouth Bancshares, 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, requests for a paper copy of proxy materials must be received by April 13, 2026.