Prosperity Bancshares (PB) completes Southwest Bancshares and Texas Partners Bank merger

Rhea-AI Filing Summary

Prosperity Bancshares, Inc. reported that it has closed its acquisition of Southwest Bancshares, Inc. as of February 2, 2026. Under their previously signed Agreement and Plan of Merger, Southwest merged into Prosperity, with Prosperity continuing as the surviving corporation.

After this holding company merger, Texas Partners Bank, a Texas banking association and wholly owned subsidiary of Southwest, merged into Prosperity Bank, a Texas banking association and wholly owned subsidiary of Prosperity, with Prosperity Bank as the surviving bank. The company furnished a press release as an exhibit describing the transaction.

Insights

Bank M&A and regulatory disclosure analyst

Prosperity completes the previously agreed acquisition of Southwest Bancshares and folds Texas Partners Bank into Prosperity Bank.

The company states that the acquisition of Southwest Bancshares, Inc. closed on February 2, 2026, pursuant to an Agreement and Plan of Merger dated September 30, 2025. Southwest merged with and into Prosperity Bancshares, Inc., with Prosperity remaining as the surviving corporation.

The filing also explains a follow-on bank merger: Texas Partners Bank, a Texas banking association and wholly owned subsidiary of Southwest, merged with and into Prosperity Bank, a Texas banking association and wholly owned subsidiary of Prosperity, with Prosperity Bank as the surviving bank. A press release attached as Exhibit 99.1 provides additional narrative about the transaction.

This event confirms legal completion of both the holding company and bank-level mergers described in earlier agreements. Any financial impact, such as changes in assets, deposits, or earnings contribution from Texas Partners Bank, is not quantified in this excerpt and would need to be evaluated from the related press release or subsequent periodic reports.

8-K Event Classification

2 items: 8.01, 9.01

2 items

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Understanding 8-K Material Events →

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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): February 2, 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 8.01 Other Events.

On February 2, 2026, Prosperity Bancshares, Inc. (“Prosperity”) issued a press release announcing the closing of the acquisition by Prosperity of Southwest Bancshares, Inc. (“Southwest”). Pursuant to the Agreement and Plan of Merger, dated as of September 30, 2025, by and between Prosperity and Southwest, Southwest merged with and into Prosperity, with Prosperity continuing as the surviving corporation (the “Merger”), and following the Merger, Texas Partners Bank, a Texas banking association and a wholly-owned subsidiary of Southwest, merged with and into Prosperity Bank, a Texas banking association and a wholly-owned subsidiary of Prosperity, with Prosperity Bank continuing as the surviving bank. A copy of Prosperity's press release is attached hereto as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d)Exhibits.

Exhibit Number		Description of Exhibit
99.1		Press Release issued by Prosperity Bancshares, Inc. dated February 2, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

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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: February 2, 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 in this 8-K?

Prosperity Bancshares announced the closing of its acquisition of Southwest Bancshares, Inc. Southwest merged with and into Prosperity, and Prosperity remained the surviving corporation. This confirms completion of the previously signed Agreement and Plan of Merger between the two bank holding companies.

What happened to Texas Partners Bank in the Prosperity Bancshares (PB) deal?

Following the holding company merger, Texas Partners Bank, a Texas banking association and wholly owned subsidiary of Southwest, merged with and into Prosperity Bank. Prosperity Bank, also a Texas banking association and wholly owned subsidiary of Prosperity, continued as the surviving bank in this transaction.

When did Prosperity Bancshares (PB) complete the Southwest Bancshares acquisition?

Prosperity Bancshares completed the acquisition of Southwest Bancshares, Inc. on February 2, 2026. That same date is identified as the date of the earliest event reported in the 8-K and is also the date on the related press release attached as an exhibit.

What legal agreement governed Prosperity Bancshares’ acquisition of Southwest Bancshares?

The acquisition was governed by an Agreement and Plan of Merger dated September 30, 2025, between Prosperity Bancshares, Inc. and Southwest Bancshares, Inc. This agreement provided for Southwest merging with and into Prosperity, with Prosperity continuing as the surviving corporation after the merger.

Which exhibit in the Prosperity Bancshares (PB) 8-K contains more details on the merger?

Exhibit 99.1 to the 8-K contains a press release issued by Prosperity Bancshares, Inc. dated February 2, 2026. That press release provides additional information about the closing of the acquisition of Southwest Bancshares and the related bank-level merger involving Texas Partners Bank and Prosperity Bank.

What type of banks are Prosperity Bank and Texas Partners Bank in this transaction?

Both Prosperity Bank and Texas Partners Bank are described as Texas banking associations. Before the merger, Texas Partners Bank was a wholly owned subsidiary of Southwest, and Prosperity Bank was a wholly owned subsidiary of Prosperity Bancshares, with Prosperity Bank remaining the surviving bank after their merger.