CoastalSouth Bancshares, Inc.

Item 5.03 Amendments to Articles of Incorporation or Bylaws. On July 23, 2026, the Board of Directors of CoastalSouth Bancshares, Inc. (the "Company") approved an amendment to the Company's Amended and Restated Bylaws, effective immediately, adding a new Article XII relating to exclusive forum and standing requirements for certain disputes. The amendment provides that, unless the Company consents in writing to the selection of an alternative forum, the Georgia State-wide Business Court will be the sole and exclusive forum for internal entity claims (as defined in the Georgia Business Corporation Code), including proceedings relating to the court-ordered inspection of corporate records by shareholders. The provision expressly does not apply to direct claims arising under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended. The amendment also establishes a minimum ownership requirement for shareholders seeking to commence or maintain a derivative proceeding on behalf of the Company. Under the amendment, a shareholder must have owned at least one percent (1%) of the Company's issued and outstanding shares at the time of the acts or omissions giving rise to the derivative proceeding in order to have standing to commence or maintain such action. The foregoing description of the amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the amendment to the Company's Amended and Restated Bylaws, which is filed as Exhibit 3.2 to this Current Report on Form 8-K and is incorporated herein by reference.