Prosperity Bancshares (PB) plans stock merger with Stellar Bancorp and banks

Rhea-AI Filing Summary

Prosperity Bancshares announced that it has signed an Agreement and Plan of Merger with Stellar Bancorp, under which Stellar will merge into Prosperity, with Prosperity as the surviving corporation. Immediately afterward, Stellar Bank is expected to merge into Prosperity Bank, which will remain as the surviving bank.

The companies issued a joint press release and an investor presentation outlining the proposed transaction, both furnished as exhibits to this report. Prosperity plans to file a registration statement on Form S-4, including a joint proxy statement/prospectus, so Stellar shareholders can vote on the merger and receive Prosperity common stock as consideration.

Insights

Bank M&A and capital markets analyst

Prosperity and Stellar agree to a stock-for-stock bank merger, pending approvals.

Prosperity Bancshares and Stellar Bancorp have executed a definitive merger agreement where Stellar will be combined into Prosperity, followed by a merger of Stellar Bank into Prosperity Bank. Prosperity will issue common stock to Stellar shareholders, with full terms to appear in a Form S-4.

The transaction requires Stellar shareholder approval and multiple regulatory approvals, and the companies highlight typical integration and execution risks, including potential delays, higher-than-expected costs, business disruption, and customer or employee reactions. They also flag dilution from additional Prosperity common shares issued in the merger.

Because specific financial terms, expected synergies, and timing are not detailed here, the overall impact depends on factors that will be described in the forthcoming S-4 registration statement and proxy statement/prospectus and on subsequent regulatory and shareholder decisions.

PROSPERITY BANCSHARES INC NYSE false 0001068851 0001068851 2026-01-28 2026-01-28

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): January 28, 2026

PROSPERITY BANCSHARES, INC.

(Exact name of registrant as specified in its charter)

Texas		001-35388		74-2331986
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

4295 San Felipe

Houston, Texas 77027

(Address of principal executive offices including zip code)

Registrant’s telephone number, including area code: (281) 269-7199

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☒ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common stock, par value $1.00 per share		PB		New York Stock Exchange, Inc.

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 7.01. Regulation FD Disclosure.

On January 28, 2026, Prosperity Bancshares, Inc., a Texas corporation (“Prosperity”) and Stellar Bancorp, Inc., a Texas corporation (“Stellar”) issued a joint press release announcing the execution of an Agreement and Plan of Merger (the “Merger Agreement”), dated as of January 27, 2026, by and between Prosperity and Stellar, pursuant to which, upon the terms and subject to the conditions set forth therein, Stellar will merge with and into Prosperity (the “Merger”), with Prosperity continuing as the surviving corporation in the Merger. Immediately following the Merger, Stellar’s wholly owned banking subsidiary, Stellar Bank, will merge with and into Prosperity’s wholly owned banking subsidiary, Prosperity Bank (the “Bank Merger”), which will continue as the surviving bank in the Bank Merger. A copy of the joint press release is attached hereto as Exhibit 99.1 and is incorporated by reference herein.

In connection with the announcement of the Merger Agreement, Prosperity and Stellar intend to provide supplemental information regarding the proposed transaction in connection with presentations to analysts and investors. The slides that will be available in connection with the presentations are attached hereto as Exhibit 99.2 and are incorporated by reference herein.

The information provided under Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 and Exhibit 99.2, is being “furnished” and is not deemed to be “filed” with the SEC for the purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section and is not incorporated by reference into any filing of Prosperity under the Securities Act or the Exchange Act, whether made before or after the date hereof, except as shall be expressly set forth by specific reference to this Current Report on Form 8-K in such a filing. Prosperity does not incorporate by reference to this Current Report on Form 8-K information presented at any website referenced in this report or in any of the Exhibits attached hereto.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description of Exhibit
99.1*		Joint press release of Prosperity Bancshares, Inc. and Stellar Bancorp, Inc.
99.2*		Joint investor presentation of Prosperity Bancshares, Inc. and Stellar Bancorp, Inc.
104		Cover Page Interactive Data File - the cover page XBRL tags are embedded within the Inline XBRL document.

* Furnished, not filed.

Cautionary Notes on Forward Looking Statements

This Current Report on Form 8-K contains statements regarding the proposed transaction between Prosperity Bancshares, Inc. (“Prosperity”) and Stellar Bancorp, Inc. (“Stellar”); future financial and operating results; benefits and synergies of the proposed transaction; future opportunities for Prosperity; the issuance of common stock of Prosperity contemplated by the Agreement and Plan of Merger by and between Prosperity and Stellar (the “Merger Agreement”); the expected filing by Prosperity with the Securities and Exchange Commission (the “SEC”) of a registration statement on Form S-4 (the “Registration Statement”) and a prospectus of Prosperity and a proxy statement of Stellar to be included therein (the “Proxy Statement/Prospectus”); the expected timing of the closing of the proposed transaction; the ability of the parties to complete the proposed transaction considering the various closing conditions and any other statements about future expectations that constitute forward-looking statements within the meaning of the federal securities laws, including the meaning of the Private Securities Litigation Reform Act of 1995, as amended, Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended. From time to time, oral or written forward-looking statements may also be included in other information released to the public. Such forward-looking statements are typically, but not exclusively, identified by the use in the statements of words or phrases such as “aim,” “anticipate,” “believe,”

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“estimate,” “expect,” “goal,” “guidance,” “intend,” “is anticipated,” “is expected,” “is intended,” “objective,” “plan,” “projected,” “projection,” “will affect,” “will be,” “will continue,” “will decrease,” “will grow,” “will impact,” “will increase,” “will incur,” “will reduce,” “will remain,” “will result,” “would be,” variations of such words or phrases (including where the word “could,” “may,” or “would” is used rather than the word “will” in a phrase) and similar words and phrases indicating that the statement addresses some future result, occurrence, plan or objective. Forward-looking statements include all statements other than statements of historical fact, including forecasts or trends, and are based on current expectations, assumptions, estimates, and projections about Prosperity, Stellar and their respective subsidiaries or related to the proposed transaction between Prosperity and Stellar and are subject to significant risks and uncertainties that could cause actual results to differ materially from the results expressed in such statements.

These forward-looking statements may include information about Prosperity’s and Stellar’s possible or assumed future economic performance or future results of operations, including future revenues, income, expenses, provision for loan losses, provision for taxes, effective tax rate, earnings per share and cash flows and Prosperity’s and Stellar’s future capital expenditures and dividends, future financial condition and changes therein, including changes in Prosperity’s and Stellar’s loan portfolio and allowance for loan losses, future capital structure or changes therein, as well as the plans and objectives of management for Prosperity’s and Stellar’s future operations, future or proposed acquisitions, the future or expected effect of acquisitions on Prosperity’s and Stellar’s operations, results of operations, financial condition, and future economic performance, statements about the anticipated benefits of the proposed transaction, and statements about the assumptions underlying any such statement.

These forward-looking statements are not guarantees of future performance and are based on expectations and assumptions Prosperity and Stellar currently believe to be valid. Because forward-looking statements relate to future results and occurrences, many of which are outside of the control of Prosperity and Stellar, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. Many possible events or factors could adversely affect the future financial results and performance of Prosperity, Stellar or the combined company and could cause those results or performance to differ materially from those expressed in or implied by the forward-looking statements. Such risks and uncertainties include, among others: (1) the risk that the cost savings and synergies from the proposed transaction may not be fully realized or may take longer than anticipated to be realized, (2) disruption to Prosperity’s and Stellar’s businesses as a result of the announcements and pendency of the proposed transaction, (3) the risk that the integration of Stellar’s businesses and operations into Prosperity will be materially delayed or will be more costly or difficult than expected, or that Prosperity is otherwise unable to successfully integrate Stellar’s business into its own, including as a result of unexpected factors or events, (4) the failure to obtain the necessary approval by the shareholders of Stellar, (5) the ability by Prosperity and/or Stellar to obtain required governmental approvals of the proposed transaction on the timeline expected, or at all, and the risk that such approvals may result in the imposition of conditions that could adversely affect Prosperity after the closing of the proposed transaction or adversely affect the expected benefits of the proposed transaction, (6) reputational risk and the reaction of each company’s customers, suppliers, employees or other business partners to the proposed transaction, (7) the failure of the closing conditions in the Merger Agreement to be satisfied, or any unexpected delay in closing the proposed transaction or the occurrence of any event, change or other circumstances that could give rise to the termination of the Merger Agreement, (8) the dilution caused by the issuances of additional shares of Prosperity’s common stock in the proposed transaction, (9) the possibility that the proposed transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events, (10) the outcome of any legal or regulatory proceedings that may be currently pending or later instituted against Prosperity before or after the proposed transaction, or against Stellar, (11) diversion of management’s attention from ongoing business operations and (12) general competitive, economic, political and market conditions and other factors that may affect future results of Prosperity and Stellar. Prosperity and Stellar disclaim any obligation to update such factors or to publicly announce the results of any revisions to any of the forward-looking statements included herein to reflect future events or developments. These and various other risks, uncertainties, assumptions, and factors are discussed in the Annual Reports on Form 10-K for the year ended December 31, 2024, Quarterly Reports on Form 10-Q, and Current Reports on Form 8-K, filed by Prosperity or Stellar and in other filings made by Prosperity and Stellar with the SEC from time to time.

Additional Information about the Transaction and Where to Find It

Prosperity intends to file with the SEC the Registration Statement on Form S-4 to register the shares of Prosperity common stock to be issued to the shareholders of Stellar in connection with the proposed transaction. The Registration Statement will include the Proxy Statement/Prospectus which will be sent to the shareholders of Stellar in connection

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with the proposed transaction. This communication is not a substitute for the Registration Statement, the Proxy Statement/Prospectus or any other document that may be filed by Prosperity or Stellar with the SEC. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT, THE PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS TO BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED TRANSACTION OR INCORPORATED BY REFERENCE INTO THE PROXY/STATEMENT PROSPECTUS, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY, BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION. Investors and security holders will be able to obtain the Registration Statement and the Proxy Statement/Prospectus (when available) and other documents that are filed with the SEC by Prosperity or Stellar, as applicable, free of charge from the SEC’s website at https://www.sec.gov or through the investor relations section of Prosperity’s website at https://www.prosperitybankusa.com/investor-relations/ or Stellar’s website at https://ir.stellar.bank.

Participants in the Solicitation

Prosperity, Stellar and certain of their directors and executive officers and other employees may be deemed to be participants in the solicitation of proxies from Stellar’s shareholders in connection with the proposed transaction. Information about the directors and executive officers of Prosperity and their ownership of Prosperity common stock is contained in the definitive proxy statement for Prosperity’s 2025 annual meeting of shareholders (the “Prosperity Annual Meeting Proxy Statement”), which was filed with the SEC on March 13, 2025, including under the headings “Item 1. Election of Directors,” “Corporate Governance,” “Executive Compensation and Other Matters,” “Item 3. Advisory Vote on Executive Compensation,” and “Beneficial Ownership of Common Stock by Management of the Company and Principal Shareholders.” Information about the directors and executive officers of Stellar and their ownership of Stellar common stock is contained in the definitive proxy statement for Stellar’s 2025 annual meeting of shareholders (the “Stellar Annual Meeting Proxy Statement”), which was filed with the SEC on April 10, 2025, including under the headings “Proposal 1: Election of Directors,” “Certain Corporate Governance Matters,” “Executive Compensation and Other Matters,” “Executive Compensation Payments and Awards,” “Proposal 4: Advisory Vote on the Compensation of the Company’s Named Executive Officers (“Say-on-Pay Resolution”),” and “Beneficial Ownership of the Company’s Common Stock by Management and Principal Shareholders of the Company.” Additional information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of the shareholders of Stellar in connection with the proposed transaction, including a description of their direct or indirect interests, by security holdings or otherwise, will be included in the Proxy Statement/Prospectus relating to the proposed transaction when it is filed with the SEC. To the extent holdings of securities by potential participants (or the identity of such participants) have changed since the information printed in the Prosperity Annual Meeting Proxy Statement or the Stellar Annual Meeting Proxy Statement, such information has been or will be reflected on Statements of Change in Ownership on Forms 3 and 4 filed with the SEC, as applicable. Free copies of the Proxy Statement/Prospectus relating to the proposed transaction and free copies of the other SEC filings to which reference is made in this paragraph may be obtained from the SEC’s website at https://www.sec.gov or through the investor relations section of Prosperity’s website at https://www.prosperitybankusa.com/investor-relations/ or Stellar’s website at https://ir.stellar.bank.

No Offer or Solicitation

This communication is for informational purposes only and is not intended to and does not constitute an offer to subscribe for, buy or sell, or the solicitation of an offer to subscribe for, buy or sell, or an invitation to subscribe for, buy or sell any securities or a solicitation of any vote or approval in any jurisdiction, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in which such offer, invitation, sale or solicitation would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act, and otherwise in accordance with applicable law.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

				PROSPERITY BANCSHARES, INC. (Registrant)
Dated: January 28, 2026				By:		/s/ Charlotte M. Rasche
				Name:		Charlotte M. Rasche
				Title:		Executive Vice President and General Counsel

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FAQ

What transaction did Prosperity Bancshares (PB) announce with Stellar Bancorp?

Prosperity Bancshares and Stellar Bancorp signed a definitive merger agreement. Stellar will merge into Prosperity, with Prosperity as the surviving corporation, followed by a merger of Stellar Bank into Prosperity Bank, which will remain as the surviving bank after completion.

How will Stellar Bancorp shareholders be compensated in the Prosperity (PB) merger?

Stellar shareholders are expected to receive Prosperity common stock. Prosperity plans to file a Form S-4 registration statement that will register the Prosperity shares issued in the merger and include a proxy statement/prospectus describing the consideration and terms in detail.

What approvals are required for the Prosperity Bancshares–Stellar Bancorp merger?

The merger needs Stellar shareholder and governmental approvals. Closing is subject to approval by Stellar shareholders, required regulatory approvals that may impose conditions, satisfaction of closing conditions in the merger agreement, and the absence of events that could trigger termination.

What key risks does Prosperity (PB) highlight regarding the Stellar merger?

Management cites integration, cost, approval, and dilution risks. They reference potential delays or higher costs in integrating Stellar, business disruption, failure to obtain approvals, possible termination of the merger agreement, reputational impacts, legal proceedings, and dilution from issuing additional Prosperity common shares.

Will Prosperity Bancshares (PB) and Stellar Bancorp issue more detailed merger information?

Yes, more detailed information will be provided in SEC filings. Prosperity intends to file a Form S-4 registration statement containing a joint proxy statement/prospectus. Stellar shareholders will receive this document and are urged to read it carefully when available, as it will contain important details.

Where can investors find the Prosperity–Stellar merger documents?

Investors can access filings on the SEC and company websites. The Form S-4, proxy statement/prospectus, and related documents will be available free at the SEC’s website, and through the investor relations sections of Prosperity’s and Stellar’s respective corporate websites.