Stellar Bancorp (NYSE: STEL) holders get Prosperity stock plus $11.36 cash

Rhea-AI Filing Summary

Stellar Bancorp, Inc. has completed its merger into Prosperity Bancshares, Inc., with Prosperity as the surviving corporation. Each share of Stellar common stock was converted into the right to receive 0.3803 shares of Prosperity common stock plus $11.36 in cash per share, along with cash instead of any fractional shares.

Stellar Bank was merged into Prosperity Bank, which continues as the surviving bank. Trading in Stellar’s common stock on the NYSE was suspended and the listing withdrawn, and Prosperity, as successor, plans to deregister Stellar’s shares and end its SEC reporting obligations. As of the merger’s effective time, Stellar’s directors and officers ceased their roles, while two former Stellar directors joined Prosperity’s board.

In connection with closing the transactions, Stellar undertook a balance sheet repositioning, selling approximately $466.4 million of investment securities, including various mortgage-backed, municipal, and corporate debt securities, before June 30, 2026.

Insights

Banking M&A analyst

Stellar is absorbed into Prosperity with mixed stock-and-cash consideration and NYSE delisting.

The merger makes Prosperity Bancshares the surviving holding company and bank platform, with Stellar shareholders receiving 0.3803 Prosperity shares plus $11.36 cash per Stellar share. This fully replaces their prior standalone equity stake in Stellar with a combination of Prosperity stock and cash.

Stellar’s NYSE-listed shares are being delisted and deregistered, ending its separate public reporting. Governance and organizational control shift to Prosperity’s existing structure, with only two former Stellar directors joining Prosperity’s board. This consolidates oversight under Prosperity’s charter and bylaws.

The disclosed balance sheet repositioning involved sales of about $466.4 million of investment securities ahead of closing. That step adjusts the combined entity’s asset mix and securities portfolio composition, though the excerpt does not quantify related gains, losses, or capital effects, so investors must look to future Prosperity filings for detailed financial impact.

8-K Event Classification

8 items: 2.01, 3.01, 3.03, 5.01, 5.02, 5.03, 8.01, 9.01

8 items

Item 2.01 Completion of Acquisition or Disposition of Assets Financial

The company completed a significant acquisition or sale of business assets.

Item 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing Securities

The company received a delisting notice or transferred its listing to a different exchange.

Item 3.03 Material Modification to Rights of Security Holders Securities

A change was made that materially affects the rights of existing shareholders (e.g., dividend rights, voting rights).

Item 5.01 Changes in Control of Registrant Governance

A change in control of the company occurred, such as through a merger, takeover, or management buyout.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers Governance

Key personnel changes including departures, elections, or appointments of directors and executive officers.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year Governance

The company amended its charter documents, bylaws, or changed its fiscal year.

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.

Key Figures

Stock consideration per Stellar share: 0.3803 shares Cash consideration per Stellar share: $11.36 per share Securities sold for repositioning: $466.4 million +2 more

5 metrics

Stock consideration per Stellar share 0.3803 shares Prosperity common stock per share of Stellar common stock at Effective Time

Cash consideration per Stellar share $11.36 per share Per Share Cash Consideration in merger

Securities sold for repositioning $466.4 million Investment portfolio securities sold during period ending June 30, 2026

Merger closing date July 1, 2026 Date Stellar merged into Prosperity and banks combined

Delisting notification date June 30, 2026 Date Stellar notified NYSE of merger consummation and requested delisting

Key Terms

Exchange Ratio, Per Share Cash Consideration, Per Share Merger Consideration, balance sheet repositioning strategy, +2 more

6 terms

Exchange Ratio financial

"each share of common stock... was converted into the right to receive (i) 0.3803 shares of common stock (the “Exchange Ratio”)"

The exchange ratio is the number used to decide how many shares of one company you get for each share you own in another company during a merger or acquisition. It’s like a recipe that tells you how to swap shares fairly, ensuring both companies’ values are balanced. This ratio matters because it determines how ownership divides between the companies' shareholders.

Per Share Cash Consideration financial

"an amount in cash equal to $11.36 (the “Per Share Cash Consideration”)"

The amount of cash offered to buy each share of a company in a transaction, such as a takeover or buyout. Think of it as the dollar price a buyer promises to hand over for every share you own; it matters to investors because it determines the immediate cash value they would receive, whether the offer is above or below current market price, and helps compare competing bids or evaluate fairness.

Per Share Merger Consideration financial

"(i) and (ii) together, the “Per Share Merger Consideration”"

balance sheet repositioning strategy financial

"Stellar executed a balance sheet repositioning strategy."

Form 25 regulatory

"file with the Securities and Exchange Commission notifications of delisting of Stellar Common Stock on Form 25"

A Form 25 is an official filing with the U.S. Securities and Exchange Commission used to remove a company's stock or other security from a national exchange list. Investors should care because delisting often means less visibility, lower trading volume and wider price swings—similar to a product moving from a major supermarket to a small local market, which can make buying, selling and valuing the security more difficult.

Form 15 regulatory

"intends to file with the SEC a certification on Form 15 requesting the deregistration of Stellar Common Stock"

A Form 15 is a short filing a public company uses with the U.S. Securities and Exchange Commission to stop or pause its routine public reporting requirements when it meets certain legal thresholds (such as a low number of public shareholders) or other qualifying conditions. Investors should care because filing one typically means less public financial information and lower trading liquidity—similar to a shop taking down its public notice board, making it harder to track performance and buy or sell shares.

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FAQ

What happened to Stellar Bancorp (STEL) in this 8-K filing?

Stellar Bancorp completed its merger into Prosperity Bancshares, with Prosperity as the surviving corporation. Stellar Bank merged into Prosperity Bank, and Stellar’s separate corporate existence and NYSE listing effectively ended at the merger’s effective time.

What consideration do Stellar Bancorp (STEL) shareholders receive in the merger?

Each Stellar share converts into 0.3803 shares of Prosperity common stock plus $11.36 in cash, plus cash for any fractional Prosperity shares. This stock-and-cash package replaces prior Stellar holdings with a combined Prosperity stake and immediate cash payment.

What happens to Stellar Bancorp’s NYSE listing after the merger?

Trading of Stellar common stock on the NYSE was suspended before the July 1, 2026 open, and the stock is being withdrawn from listing. A Form 25 will be filed to delist and deregister the shares under Section 12(b) of the Exchange Act.

Will Stellar Bancorp (STEL) continue filing reports with the SEC?

Prosperity, as successor to Stellar, intends to file a Form 15 to deregister Stellar’s common stock under Section 12(g) and suspend its reporting duties under Sections 13 and 15(d). After effectiveness, Stellar will no longer file standalone periodic SEC reports.

Were there any balance sheet actions tied to the Stellar–Prosperity merger?

Yes. In connection with closing, Stellar executed a balance sheet repositioning strategy, selling about $466.4 million of investment securities, including agency mortgage-backed, municipal, and corporate debt securities during the period ending June 30, 2026.

Did any Stellar Bancorp directors join Prosperity Bancshares’ board?

Two former Stellar directors, Robert R. Franklin, Jr. and Joseph B. Swinbank, were appointed to Prosperity’s board at the merger’s effective time. All Stellar directors and executive officers ceased serving in their roles at Stellar when the merger closed.

false 0001473844 --12-31 0001473844 2026-07-01 2026-07-01

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): July 1, 2026

STELLAR BANCORP, INC.

(Exact name of registrant as specified in its charter)

Texas		001-38280		20-8339782
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

9 Greenway Plaza, Suite 110

Houston, Texas 77046

(Address of principal executive offices including zip code)

Registrant’s telephone number, including area code: (713) 210-7600

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 $0.01 per share		STEL		New York Stock Exchange
Indicate by check mark whether
				NYSE Texas

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 2.01 Completion of Acquisition or Disposition of Assets.

On July 1, 2026, Stellar Bancorp, Inc., a Texas corporation (“Stellar”), merged (the “Merger”) with and into Prosperity Bancshares, Inc., a Texas corporation (“Prosperity”), with Prosperity continuing as the surviving corporation (the “Surviving Corporation”) in the Merger pursuant to the Agreement and Plan of Merger, dated as of January 27, 2026 (the “Merger Agreement”), by and between Prosperity and Stellar.

Immediately following the Merger, Stellar Bank, a Texas banking association and wholly owned subsidiary of Stellar, merged with and into Prosperity Bank, a Texas banking association and wholly owned subsidiary of Prosperity (the “Bank Merger” and together with the Merger, the “Transactions”), with Prosperity Bank continuing as the surviving bank in the Bank Merger.

Pursuant to the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock, par value $0.01 per share, of Stellar (“Stellar Common Stock”) outstanding immediately prior to the Effective Time, other than certain shares held by Prosperity or Stellar, was converted into the right to receive (i) 0.3803 shares of common stock (the “Exchange Ratio”), par value $1.00 per share, of Prosperity (“Prosperity Common Stock”), (ii) an amount in cash equal to $11.36 (the “Per Share Cash Consideration”) ((i) and (ii) together, the “Per Share Merger Consideration”) and (iii) cash in lieu of fractional shares.

Pursuant to the Merger Agreement, at the Effective Time:

• Stellar Stock Options. Each Stellar stock option with a per-share exercise price that was less than the Per Share Merger Consideration Value was cancelled and the holder of such cancelled stock option received (without interest) an amount in cash equal to the product of (A) the excess of the Per Share Merger Consideration Value over the stock option’s per-share exercise price, multiplied by (B) the number of shares of Stellar Common Stock subject to such stock option immediately prior to the Effective Time. Any Stellar stock option with a per-share exercise price that was equal to or greater than the Per Share Merger Consideration Value was cancelled for no consideration in respect thereof. “Per Share Merger Consideration Value” means the sum of (1) the Per Share Cash Consideration plus (2) the product of (x) the Exchange Ratio multiplied by (y) $71.44, which equaled the average closing sale price of Prosperity Common Stock for the 10 consecutive full trading days ending on and including the fifth trading day immediately preceding the Closing Date.

• Stellar Restricted Stock Awards. Each outstanding restricted stock award in respect of Stellar Common Stock subject solely to service-based vesting, repurchase or other lapse restriction fully vested and was converted into the right to receive (without interest) the Per Share Merger Consideration.

• Stellar Performance Unit Awards. Each outstanding restricted unit award in respect of Stellar Common Stock subject to performance-based vesting (each, a “performance unit award”) fully vested and was converted into the right to receive (without interest) a cash payment equal to the product of (a) the Per Share Merger Consideration Value multiplied by (b) the number of shares of Stellar Common Stock subject to such performance unit award, with applicable performance deemed achieved at 100% of the target level (or, in the case of the performance unit awards granted in 2024, 200% of the target level).

The foregoing description of the Transactions and the Merger Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Merger Agreement, a copy of which is filed as Exhibit 2.1 and incorporated herein by reference.

Item 3.01. Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing.

On June 30, 2026, Stellar notified the New York Stock Exchange (the “NYSE”) of the consummation of the Merger and requested that the NYSE (i) suspend trading of Stellar Common Stock prior to the opening of trading on July 1, 2026, (ii) withdraw Stellar Common Stock from listing on the NYSE prior to the opening of trading on July 1, 2026, and (iii) file with the Securities and Exchange Commission (the “SEC”) notifications of delisting of Stellar Common Stock on Form 25 and deregistration under Section 12(b) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). As a result, Stellar Common Stock will no longer be listed on the NYSE.

2

Additionally, Prosperity, as successor to Stellar, intends to file with the SEC a certification on Form 15 requesting the deregistration of Stellar Common Stock under Section 12(g) of the Exchange Act and the suspension of Stellar’s reporting obligations under Sections 13 and 15(d) of the Exchange Act as promptly as practicable.

The information set forth under Item 2.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.01.

Item 3.03. Material Modification to Rights of Security Holders.

As of the Effective Time, each holder of a certificate or book-entry share representing any shares of Stellar Common Stock ceased to have any rights with respect thereto, except the right to receive the consideration as described above and subject to the terms and conditions set forth in the Merger Agreement.

The information set forth under Items 2.01, 3.01, 5.01 and 5.03 of this Current Report on Form 8-K is incorporated by reference into this Item 3.03.

Item 5.01. Changes in Control of the Registrant.

The information set forth under Items 2.01, 3.01, 3.03 and 5.02 of this Current Report on Form 8-K is incorporated by reference into this Item 5.01.

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

As of the Effective Time, and pursuant to the terms of the Merger Agreement, Stellar’s directors and executive officers ceased serving as directors and executive officers of Stellar. In addition, as of the Effective Time and in accordance with the Merger Agreement, Robert R. Franklin, Jr. and Joseph B. Swinbank, each of whom was a member of the board of directors of Stellar immediately prior to the consummation of the Merger, were appointed to the board of directors of Prosperity.

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

At the Effective Time, the Second Amended and Restated Certificate of Formation and Amended and Restated Bylaws of Stellar ceased to be in effect by operation of law. As a result of the Merger, Prosperity’s Amended and Restated Articles of Incorporation, as amended, and Amended and Restated Bylaws, copies of which are included as Exhibits 3.1, 3.2 and 3.3 hereto, respectively, and incorporated by reference herein, continued in effect as the governing documents of the Surviving Corporation.

The information set forth under Item 2.01 of this Current Report on Form 8-K is incorporated by reference into this Item 5.03.

Item 8.01. Other Events.

Balance Sheet Repositioning

In connection with the closing of the Transactions, Stellar executed a balance sheet repositioning strategy. As part of this strategy, during the period ending June 30, 2026, Stellar sold approximately $466.4 million of securities from its investment portfolio, which included agency mortgage-backed securities, agency commercial mortgage-backed securities, collateralized mortgage obligations, municipal securities, and corporate debt and other securities.

3

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description of Exhibit
2.1		Agreement and Plan of Merger, dated as of January 27, 2026, by and between Prosperity Bancshares, Inc. and Stellar Bancorp, Inc. (incorporated by reference to Exhibit 2.1 to Stellar’s Current Report on Form 8-K, filed with the SEC on January 29, 2026)
3.1		Amended and Restated Articles of Incorporation of Prosperity Bancshares, Inc. (incorporated herein by reference to Exhibit 3.1 to the Prosperity Bancshares, Inc.’s Registration Statement on Form S-1 (Registration No. 333-63267))
3.2		Articles of Amendment to Amended and Restated Articles of Incorporation of Prosperity Bancshares, Inc. (incorporated herein by reference to Exhibit 3.2 to the Prosperity Bancshares, Inc.’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2006 (File No. 001-35388))
3.3		Amended and Restated Bylaws of Prosperity Bancshares, Inc. (incorporated herein by reference to Exhibit 3.1 to the Prosperity Bancshares, Inc.’s Current Report on Form 8-K filed June 20, 2019 (File No. 001-35388))
104		Cover Page Interactive Data File - the cover page XBRL tags are 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. (as successor by merger to the registrant)
Dated: July 1, 2026				By:		/s/ Charlotte M. Rasche
				Name:		Charlotte M. Rasche
				Title:		Executive Vice President and General Counsel

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Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 18.3 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.4 KB