Third Coast Bancshares and Great Plains Bancshares announce the signing of a final merger agreement

After the transaction is completed, the total assets after consolidation are expected to exceed $9 billion.

Houston and Oklahoma City, October 7, 2026 / PRNewswire / -- Third Coast Bancshares, Inc. (Referred to as “Third Coast”, with codes NYSE and NYSE Texas: TCBX) – The parent company of Third Coast Bank – and Great Plains Bancshares, Inc. (Referred to as “Great Plains”) – the parent company of Great Plains National Bank – jointly announced today that both parties have signed a final merger agreement. According to the agreement, Third Coast will acquire Great Plains through a wholly stock transaction. Based on Third Coast's closing stock price as of October 6, 2026, the value of this transaction is approximately $239.6 million. On a pro-forma basis, after the completion of the transaction, the combined company's asset size is expected to be around $9 billion.

This strategic cooperation will provide integration opportunities for two community banks that share cultural affinities and are relationship-driven. It will also expand the presence of Third Coast in Dallas and facilitate Third Coast's entry into the Oklahoma market. Great Plains, headquartered in Oklahoma City, Oklahoma, has been operating in its service area for over 100 years and currently has 23 branches in both Oklahoma and Texas.

Third Coast Founder, Chairman, President, and CEO Bart Caraway stated: "We are very pleased to join hands with Great Plains. It is an outstanding bank that has built a strong network of relationships in Oklahoma and North Texas, boasts an excellent team, and has established a good reputation by always putting the interests of its customers first. Through this merger, we will create an institution that is larger in scale, more capable, and better equipped to support our customers. This combination will enhance our ability to serve businesses and communities in various markets, while creating long-term value for all stakeholders."

Great Plains National Bank CEO Mark Russell stated: " Great Plains is built on a belief that strong relationships can create powerful communities. As we look to the future, it is crucial to find a banking partner with shared beliefs. Third Coast's commitment to relationship-based banking, localized leadership, and community investment makes this collaboration an obvious choice. Together, we can not only carry on our own history but also expand opportunities for our customers and employees, and advance our common mission of fostering community growth in the markets we serve."

Transaction Details

According to the terms of the merger agreement, Thunder Merger Sub, a wholly-owned subsidiary of Third Coast, and Inc will be merged into Great Plains. Shareholders of Great Plains will exchange their holdings of Great Plains common shares for Third Coast common shares. After the merger is completed, Great Plains will be merged into Third Coast, and Great Plains National Bank will be merged into Third Coast Bank. Great Plains will continue to operate under the Great Plains Bank brand as a division of Third Coast Bank. Third Coast will continue to trade on the New York Stock Exchange and NYSE Texas under the stock code “TCBX”.

Third Coast is expected to issue 5,570,352 ordinary shares. According to the preparation criteria, Third Coast shareholders will hold approximately 78% of the equity in the merged company, while Great Plains shareholders will hold about 22% of the equity. Two representatives from Great Plains will be appointed to the boards of directors of Third Coast and Third Coast Bank. The CEO of Great Plains, Mr. Russell, has also agreed to continue serving in his leadership role after the completion of the transaction.

This transaction has been unanimously approved by the boards of directors of both companies and is expected to be completed in the first quarter of 2027. However, it still requires customary regulatory approvals and fulfillment of other closing conditions. For the completion of the transaction, the merger agreement must also be approved by the shareholders of Great Plains, and the issuance of Third Coast common shares in accordance with the merger agreement also requires the approval of the shareholders of Third Coast.

The consultants for Third Coast are Keefe, Bruyette & Woods (companies under Stifel, serving as financial consultants) and Norton Rose Fulbright US LLP (serving as legal consultants). The consultants for Great Plains are Stephens Inc (serving as financial consultant) and Fenimore Kay Harrison LLP (serving as legal consultant).

Presentation materials

The slide presentation materials related to this transaction can be found in the “Events & Presentations” section of the Third Coast official website: https :// ir.thirdcoast.bank / events-and-presentations / presentations /.

Regarding Third Coast Bancshares, Inc.

Third Coast Bancshares, Inc is a bank holding company that focuses on commercial banking services, headquartered in Texas. It primarily operates through its wholly-owned subsidiary, Third Coast Bank, in the markets of Greater Houston, Dallas-Fort Worth, and Austin-San Antonio. Third Coast Bank was established in Humble, Texas, in 2008, and currently conducts banking business in Texas' four major metropolitan areas through 20 branches. For more information, please visit: www.thirdcoast.bank.

Regarding Great Plains Bancshares, Inc.

Great Plains Bancshares and Inc are the bank holding companies of Great Plains National Bank. Great Plains National Bank is headquartered in Oklahoma City, Oklahoma, and has served the western part of Oklahoma and surrounding markets for over 100 years. It has also expanded into the Oklahoma City metropolitan area and northern Texas, with 23 branches in both Oklahoma and Texas. As of June 30, 2026, Great Plains reported total assets of approximately $1.9 billion, total loans of approximately $1.7 billion, and total deposits of approximately $1.7 billion. For more information, please visit: www.gpbankok.com.

Forward-looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, which are subject to risk and uncertainty, and are made under the safe harbor provisions of Section 27A of the Revised Securities Act of 1933 and Section 21E of the Revised Securities Exchange Act of 1934. These forward-looking statements reflect Third Coast's current views regarding future events and its financial performance, among other things, including but not limited to the anticipated completion time of the proposed transaction, financial benefits, and other effects.

Such statements are typically, but not always, made using words or phrases with forward-looking implications such as "may", "should", "be able to", "predict", "potential", "believe", "look forward to", "is likely to result in", "expect", "continue", "will", "anticipate", "seek", "estimate", "intend", "plan", "forecast", "will", and "prospects", as well as their negative forms. These forward-looking statements are not historical facts, but are based on current expectations, estimates, and forecasts regarding the industry in which Third Coast operates, management's beliefs, and various assumptions made by management. Many of these assumptions are inherently uncertain and beyond the control of Third Coast. Therefore, Third Coast reminds that any such forward-looking statements do not constitute guarantees of future performance and are subject to unpredictable risks, assumptions, and uncertainties. Although Third Coast believes that the expectations reflected in these forward-looking statements at the time of their formulation are reasonable, actual results may differ significantly from those stated or implied in the forward-looking statements.

Important factors that could lead to significant differences between the actual results of Third Coast and those indicated in these forward-looking statements include, but are not limited to: (1) the occurrence of any events, changes, or other circumstances that may give either party or both parties the right to terminate the final merger agreement regarding Third Coast's acquisition of Great Plains; (2) the outcome of any legal proceedings that may be initiated against Third Coast or Great Plains; (3) the possibility that the transaction will not be completed as expected or may not be completed at all due to the failure to obtain or meet required regulatory approvals, shareholder approvals, or other conditions for completion in a timely manner or at all (and the risk that such approvals may include terms unfavorable to the expected benefits of the merged company or the transaction); (4) the risk that transaction benefits may not be fully realized or may be realized later than expected, including due to overall economic and market conditions, interest rates and exchange rates, monetary policies, laws and regulations and their enforcement, as well as changes in the competitive environment in the regions and business sectors where Third Coast and Great Plains operate or issues arising therefrom; (5) disruptions to the businesses of both parties due to the announcement and pending completion of the transaction; (6) significant delays in the integration of the businesses of both parties, or integration costs higher than expected, greater difficulties than anticipated, or the risk that both parties may not be able to successfully integrate their respective businesses into each other's; (7) transaction completion costs that may be higher than expected, including due to unexpected factors or events; (8) reputational risks and adverse reactions from Third Coast or Great Plains's customers, suppliers, employees, or other business partners, including reactions triggered by the announcement or completion of the transaction; (9) dilution resulting from the issuance of additional common shares as part of this transaction; (10) significant adverse changes in the financial conditions of Third Coast or Great Plains.(11) Overall competitive, economic, political, and market environments; (12) Major disasters such as earthquakes, floods, or other natural or man-made disasters, including outbreaks of infectious diseases; (13) Management diverting attention and time away from ongoing operations and business opportunities to matters related to mergers and acquisitions; and (14) Other factors that may affect the future performance of Third Coast and Great Plains, including changes in asset quality and credit risk, the inability to maintain revenue and profit growth, changes in interest rates and capital markets, inflation, customer lending and repayment behaviors, the extent and timing of the impact of technological changes, capital management activities, as well as other actions by the Federal Reserve Board and legislative regulatory measures and reforms.

For other factors that may lead to a significant difference between the actual results of Third Coast and the results stated in the forward-looking statements, please refer to the risk factors discussed in Third Coast's annual 10-K report for the year ending December 31, 2025, submitted to the U.S. Securities and Exchange Commission (SEC), as well as other documents submitted to SEC.

The above factors should not be considered an exhaustive list and should be read in conjunction with other cautionary statements in this press release. If one or more events related to these or other risks and uncertainties occur, or if the underlying assumptions of Third Coast prove to be incorrect, the actual results may differ significantly from those anticipated by Third Coast. Therefore, reliance on any such forward-looking statements should not be excessive. Any forward-looking statements represent the situation as of the date they are made, and Third Coast assumes no obligation to update or review any forward-looking statements due to new information, future developments, or other reasons. New factors may emerge from time to time, and Third Coast cannot predict which factors may arise. Furthermore, Third Coast is also unable to assess the impact of each factor on its business, or to determine to what extent any single factor or combination of factors may cause the actual results to differ significantly from the content contained in any forward-looking statements.

Forced solicitation or recruitment

This communication is issued regarding the proposed merger transaction between Third Coast and Great Plains. This communication does not constitute an offer to sell any securities or an invitation to purchase any securities, nor does it constitute a solicitation for any voting rights or approval; in any jurisdiction, it is illegal to sell any securities if such offers, solicitations, or sales are made before registration or qualification is completed in accordance with that jurisdiction's securities laws. Any offer of securities may only be made through a prospectus that complies with the requirements of Section 10 of the revised Securities Act of 1933, and in other respects, in accordance with the applicable laws.

Important supplementary information and methods of obtaining it

Third Coast intends to submit a registration statement for Form S to SEC, which will include a joint power of attorney between Great Plains and Third Coast. This document will also constitute the prospectus for Third Coast. Third Coast will also submit other documents to SEC regarding the proposed transaction. The final version of the joint power of attorney/prospectus will also be sent to the shareholders of Great Plains and Third Coast to seek the required shareholder approval.

The company urges investors and security holders to read the Form S -4 registration statement and the power of attorney/prospectus contained therein once the relevant documents are available, as well as any other related documents submitted to SEC or incorporated by reference into the Form S -4 registration statement and power of attorney/prospectus that are related to this transaction. These documents will contain important information regarding Third Coast, Great Plains, this transaction, and related matters.

The documents submitted by Third Coast to SEC can be obtained for free on the website SEC at www.sec.gov. In addition, the documents submitted by Third Coast can also be obtained for free on their website at https :// ir.thirdcoast.bank / financials / sec-filings. Alternatively, after the documents become available, they can be requested in writing from Third Coast Bancshares, Inc, Attn : Investor Relations, 1800 West Loop South, Suite 875, Houston, TX 77027, or by calling (713) 960-1300 for free.

Parties involved in this transaction

Third Coast, Great Plains, their respective directors and executives, as well as some of their other management personnel and employees, may be considered participants in soliciting proxy votes from the shareholders of Great Plains and Third Coast regarding the proposed transaction. Information regarding the directors and executives of Third Coast can be found in Third Coast's annual 10-K report for the year ending December 31, 2025 (submitted to SEC on March 4, 2026), as well as in the Third Coast 2026 annual general meeting of shareholders proxy form (submitted to SEC on April 16, 2026); the aforementioned documents are available for free from the Third Coast or SEC websites in the manner mentioned above. If there are any changes to the number of Third Coast securities held by the directors and executives of Third Coast since the amounts listed in the 2026 annual general meeting of shareholders proxy form, such changes will have been or will be disclosed through the submission of a Form 'Beneficial Ownership Change Statement' to SEC. Further information regarding the interests of these participants and other individuals who may be considered transaction participants will be disclosed when a joint proxy form/prospectus and other relevant materials are submitted to SEC.

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