CoastalSouth Bancshares, Inc. Fair Value Disclosure

NOTE 17 — FAIR VALUE OF FINANCIAL INSTRUMENTS

US GAAP provides a framework for measuring and disclosing fair value which requires disclosures about the fair value of assets and liabilities recognized in the balance sheet, whether the measurements are made on a recurring basis (for example, available-for-sale investment securities) or on a nonrecurring basis (for example, collateral-dependent loans).

Fair value is defined as the exchange in price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. US GAAP also establishes a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.

The Company utilizes fair value measurements to record fair value adjustments to certain assets and to determine fair value disclosures. Securities available-for-sale are recorded at fair value on a recurring basis. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as loans held for sale, loans held for investment and certain other assets. These nonrecurring fair value adjustments typically involve application of lower of cost or market accounting or write-downs of individual assets.

Fair Value Hierarchy

The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine the fair value. These levels are:

Level 1 Valuation is based upon quoted prices for identical instruments traded in active markets.

Level 2 Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market.

Level 3 Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include the use of option pricing models, discounted cash flow models and similar techniques.

Following is a description of valuation methodologies used for assets and liabilities recorded at fair value.

Securities AFS — Securities AFS are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security's credit rating, prepayment assumptions and other factors such as credit loss assumptions. Level 1 securities include those traded on an active exchange such as the New York Stock Exchange, Treasury securities that are traded by dealers or brokers in active over-the-counter markets and money market funds. Level 2 securities include mortgage-backed securities issued by government sponsored entities, municipal bonds and corporate debt securities. Securities classified as Level 3 include asset-backed securities in less liquid markets.

Equity Securities — Equity securities are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted prices. There were no equity securities held at December 31, 2025 and 2024.

Loans Held for Sale — Loans held for sale are comprised of loans originated for sale in the ordinary course of business and purchased with intent to sell through MBF. The fair value of loans originated for sale in the secondary market is based on purchase commitments or quoted prices for the same or similar loans and are classified as non-recurring Level 2. There were no loans held for sale requiring fair value adjustments at December 31, 2025 and 2024.

Collateral-Dependent Loans — The Company does not record loans at fair value on a recurring basis, however, from time to time, a loan is considered collateral-dependent, evaluated individually for impairment, and an allowance for credit loss is established. Collateral-dependent loans are loans where repayment is expected to be provided solely by the sale of the underlying collateral and there are no other available and reliable sources of repayment. If a loan is determined to be collateral-dependent, or if foreclosure is probable, the Company measures the net realizable value of the collateral (fair value less costs to sell) to determine the level of impairment for the loan. The valuation of collateral is supported by an appraisal, brokers price opinion, or other comparable market data. Otherwise, the Company performs a discounted cash flow analysis on the loan to determine the level of ACL needed. At December 31, 2025 and 2024, substantially all of the individually evaluated collateral-dependent loans were evaluated based upon the fair value of the collateral. Collateral-dependent loans where an

allowance is established based on the fair value of collateral require classification in the fair value hierarchy. When the fair value of the collateral is based on an observable market price or a current appraised value, the Company records the loan as nonrecurring Level 2. When an appraised value is not available or management determines the fair value of the collateral is further impaired below the appraised value and there is no observable market price, the Company records the loan as nonrecurring Level 3.

Other Real Estate Owned — Foreclosed assets are adjusted to fair value upon transfer of the loans to OREO. Real estate acquired in settlement of loans is recorded initially at estimated fair value of the property less estimated selling costs at the date of foreclosure. The initial recorded value may be subsequently reduced by additional allowances, which are charges to earnings if the estimated fair value of the property less estimated selling costs declines below the initial recorded value. OREO presented as measured on a non-recurring basis includes only those properties that had changes in valuation. Fair value is based upon independent market prices, appraised values of the collateral or management's estimation of the value of the collateral.

Derivative Financial Instruments — The Company’s derivative financial instruments, which are interest rate contracts, are valued using a discounted cash flow method that incorporates current market interest rates.

Level 3 assets measured at fair value on a recurring basis at December 31, 2025 and 2024 were $500 thousand. There were no changes in the value in either of those periods. There were no Level 3 liabilities measured at fair value on a recurring basis at December 31, 2025. Level 3 liabilities measured at fair value on a recurring basis at December 31, 2024 were $6 thousand.

Certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). The following table presents the assets and liabilities carried on the balance sheet by caption and by level within the valuation hierarchy (as described above) for which a nonrecurring change in fair value has been recorded during the years ended December 31, 2025 and 2024.

There were no liabilities measured at fair value on a nonrecurring basis at December 31, 2025 and 2024.

Fair Value of Financial Instruments

The following tables include the estimated fair value of the Company’s financial assets and financial liabilities. The methodologies for estimating the fair value of financial assets and financial liabilities measured on a recurring and nonrecurring basis are discussed above. The methodologies for estimating the fair value for other financial assets and financial liabilities are discussed below. The estimated fair value amounts have been determined by the Company using available market information and appropriate valuation methodologies. However, considerable judgment is required to interpret market data in order to develop the estimates of fair value. Accordingly, the estimates presented below are not necessarily indicative of the amounts the Company could realize in a current market exchange. The use of different market assumptions and/or estimation techniques may have a material effect on the estimated fair value amounts at December 31, 2025.

Cash and cash equivalents — The carrying amounts of cash and due from banks and federal funds sold approximate their fair values.

Loans held for sale — Loans held for sale are carried at the lower of cost or fair value. These loans currently consist of one-to-four family residential real estate loans originated for sale to qualified third parties. Fair value is based upon the contractual price to be received from these third parties, which may be different than cost.

Loans held for investment, net — Fair values are estimated for portfolios of loans with similar financial characteristics if collateral-dependent. Loans are segregated by type. The fair value of performing loans is calculated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect observable market information incorporating the credit, liquidity, yield and other risks inherent in the loan. The estimate of maturity is based upon the Company’s historical experience with repayments for each loan classification, modified, as required, by an estimate of the effect of the current economic and lending conditions. Fair value for significant non-performing loans is generally based upon recent external appraisals. If appraisals are not available, estimated cash flows are discounted using a rate commensurate with the risk associated with the estimated cash flows. Assumptions regarding credit risk, cash flows and discounted rates are judgmentally determined using available market information and specific borrower information.

Non-marketable equity securities — Non-marketable equity securities are carried at original cost basis, as cost approximates fair value and there is no ready market for such investments.

Deposits — The fair value of deposits with no stated maturity date, such as noninterest-bearing demand deposits, savings and money market and checking accounts, is based on the discounted value of estimated cash flows. The fair value of time deposits is based upon the discounted value of contractual cash flows. The discount rate is estimated using the rates currently offered for deposits of similar remaining maturities.

Other borrowings — The fair value of the Company’s FHLBA, line of credit and subordinated debt advances are estimated based upon the discounted value of contractual cash flows. The fair value of investment securities sold under agreements to repurchase approximates the carrying amount because of the short maturity of these borrowings. The discount rate is estimated using rates quoted for the same or similar issues or the current rates offered to the Company for debt of the same remaining maturities.