CoastalSouth Bancshares, Inc.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

(a)Unregistered Sales of Equity Securities

(b)Use of Proceeds

On July 3, 2025 we completed our IPO of 2,035,000 shares of our common stock at an IPO price of $21.50 per share, with 1,700,000 shares sold by us and 335,000 shares sold by selling shareholders. On July 30, 2025, the underwriters purchased an additional 300,000 shares from the selling shareholders, exercising their option to purchase up to 305,250 shares from the selling shareholders within 30 days following the offering. We received proceeds of $34.0 million, net of underwriting discounts and commissions of approximately $2.5 million. We expect the estimated offering expenses payable by us to be approximately $1.9 million. Piper Sandler & Co. acted as bookrunner for the IPO, and Stephens Inc. acted as lead manager for the offering. None of the expenses associated with the IPO were paid to directors, officers, affiliates, persons owning 10% or more of any class of equity securities, or to their associates, or to our affiliates.

All of the shares issued and sold in our IPO were registered under the Securities Act pursuant to a registration statement on Form S-1 (File No. 333-287854), which was declared effective by the SEC on July 1, 2025. There has been no material change in the planned use of proceeds from our IPO from those disclosed in our final prospectus dated July 1, 2025 and filed with the SEC pursuant to Rule 424(b)(4) on July 2, 2025.