Third Coast Bancshares Inc — 8-K/A exhibit

the merger; and

the issuance of common stock, par value $1.00 per share, of Third Coast (“Third Coast common stock”) to Keystone Bancshares, Inc. (“Keystone”) shareholders and the cash consideration to be paid to Keystone shareholders in connection with the merger.

a closing price of Third Coast common stock of $38.01, which was the closing price of Third Coast common stock on December 31, 2025; and

the sum of Keystone’s capital, surplus and retained earnings accounts less all intangible assets, calculated as of the calculation date and in accordance with generally accepted accounting principles of the United States consistently applied, and adjusted to reflect the payment of or accrual for all Keystone Merger Costs (as defined in the merger agreement) on an after-tax basis to the extent deducible for tax purposes equaled or exceeded $94,576,000.

Cash and cash equivalents:

Cash and due from banks

Federal funds sold

Total cash and cash equivalents

Interest bearing time deposits in other banks

Investment securities available-for-sale

Investment securities held-to-maturity

Loans, net of unearned income

Allowance for loan losses

Accrued interest receivable

Premises and equipment, net

Bank-owned life insurance

Non-marketable equity securities, at cost

Deferred tax asset, net

Derivative assets

Right-of-use asset - operating leases

Goodwill and other intangible assets

Other assets

Total assets

LIABILITIES AND SHAREHOLDERS’ EQUITY

Deposits:

Noninterest bearing

Interest bearing

Total deposits

Accrued interest payable

Derivative liabilities

Lease liability - operating leases

Other liabilities

FHLB advances

Line of credit - Senior Debt

Note payable - Subordinated Debentures, net

Total liabilities

Shareholders’ equity:

Preferred stock

Common stock

Retained earning/Surplus

Accumulated other comprehensive income

Treasury stock: at cost

Total shareholders’ equity

Total liabilities and shareholders’ equity

Interest income:

Loans, including fees

Investment securities available-for-sale

Investment securities held-to-maturity

Federal funds sold and other

Total interest income

Interest expense:

Deposit accounts

FHLB advances and other borrowings

Total interest expense

Net interest income

Provision for credit losses

Net interest income after provision for credit losses

Noninterest income:

Service charges and fees

Earnings on bank-owned life insurance

Loss on sale of investment securities available-for-sale

Gain on sales of SBA loans

Gain on sale of loans

Other

Total noninterest income

Noninterest expense:

Salaries and employee benefits

Occupancy and equipment expense

Legal and professional

Data processing and network expense

Regulatory assessments

Advertising and marketing

Software purchases and maintenance

Loan operations and other real estate owned expense

Telephone and communications

Other

Total noninterest expense

Net income before income tax expense

Income tax expense

Net income

Preferred stock dividends declared

Net income available to common shareholders

Earnings per common share:

Basic earnings per share

Diluted earnings per share

This adjustment includes the cash portion of the merger consideration of $20 million and estimated pre-tax direct-incremental merger and stock issuance costs of $13.0 million ($10.8 million, after-tax).

This adjustment represents the fair value adjustments on loans. The purchase accounting adjustment for the acquired loan portfolio is comprised of approximately $3.0 million of credit adjustments for non-purchase credit deteriorated (“PCD”) assets and $588,000 of interest-rate adjustments.

This adjustment represents the elimination of Keystone’s allowance for credit losses as part of the purchase accounting transactions, offset by the creation of a $4.4 million credit adjustment on acquired PCD assets.

This adjustment represents the purchase price allocation for the merger, calculated as follows:

Issue 2,547,937 Third Coast shares valued at the closing price for Third Coast common stock on December 31, 2025

Cash merger consideration, including cash in lieu of fractional shares

Total purchase price

Keystone’s equity at book value

Allocated to loan fair value, less Keystone’s ending allowance

Allocated to core deposit intangibles

Allocated to time deposit fair value

Allocated to debt

Allocated to net deferred tax assets

Estimated goodwill from transaction

Keystone beginning goodwill balance

Net goodwill adjustment

Allocated to core deposit intangibles

Keystone beginning core deposit intangible

Goodwill and other intangible assets adjustment

This adjustment represents the impact on deferred income taxes and income tax benefits created in the accounting for the transaction, calculated as follows:

Loan fair value adjustments

Core deposit intangibles

Deposits fair value adjustments

Debt fair value adjustments

Subtotal of fair value adjustments

Calculated deferred taxes at an estimated rate of 21%

S Corp to C Corp adjustment at an estimated rate of 21%

Total deferred taxes adjustment

Tax effect of merger expenses (item (a) above)

Tax effect of creation of Allowance for Credit Losses on non-PCD assets

Total Other asset adjustment

This adjustment reflects interest-bearing time deposits at their estimated fair values.

This adjustment represents the elimination of the historical common stock of Keystone, net of the issuance of 2,547,937 shares of Third Coast common stock to shareholders of Keystone. Value of the shares issued is based on the closing price for Third Coast common stock on December 31, 2025.

This adjustment represents the elimination of the historical Retained earnings/surplus of Keystone, net of after-tax merger expenses and cost of the creation of the allowance for credit losses on non-PCD assets.

(aa)

(bb)

(cc)

(dd)

(ee)