Stellar Bancorp (STEL) CRO stock canceled, converted in Prosperity merger

Rhea-AI Filing Summary

Stellar Bancorp, Inc. Senior Executive VP and Chief Risk Officer Akin Okan I. reported a disposition to the issuer of 85,951 shares of Stellar common stock. This occurred at no stated share price in connection with the merger of Stellar Bancorp into Prosperity Bancshares, Inc.

At the effective time of the merger, each Stellar share was cancelled and converted into the right to receive 0.3803 shares of Prosperity common stock plus $11.36 in cash per share. Restricted stock and performance unit awards also vested and converted into the defined per share merger consideration or a related cash payment, and his reported direct holdings in Stellar common stock fell to zero.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Akin Okan I.

Role Senior Executive VP, CRO

Type	Security	Shares	Price	Value
Disposition	Common Stock	85,951	$0.00	--

Holdings After Transaction: Common Stock — 0 shares (Direct)

Footnotes (1)

1. Includes 66,891 shares of Company Common Stock (as defined below). On July 1, 2026 (the "Effective Time"), upon consummation of the transactions contemplated by the Agreement and Plan of Merger (the "Merger Agreement"), dated as of January 27, 2026, by and between Prosperity Bancshares, Inc., a Texas corporation ("Prosperity") and Stellar Bancorp, Inc., a Texas corporation (the "Company"), and subject to the terms and conditions set forth in the Merger Agreement, each share of the Company's common stock, par value $0.01 per share, ("Company Common Stock") outstanding immediately prior to the Effective Time was cancelled and 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") and (ii) an amount in cash equal to $11.36 (the "Per Share Cash Merger Consideration") ((i) and (ii) together, the "Per Share Merger Consideration"). Includes 6,757 shares of restricted stock. At the Effective Time, each outstanding restricted stock award in respect of Company Common Stock subject solely to service-based vesting, repurchase or other lapse restriction vested and was converted into the right to receive (without interest) the Per Share Merger Consideration. Includes (a) 4,325 performance unit awards (as defined below) granted in 2024, (b) 5,123 performance unit awards granted in 2025, and (c) 2,855 performance unit awards granted in 2026. At the Effective Time, each outstanding restricted unit award in respect of Company 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 Company Common Stock subject to such performance unit award, with applicable performance-based vesting conditions 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).

Key Figures

Shares disposed: 85,951 shares Shares after transaction: 0 shares Stock exchange ratio: 0.3803 shares +5 more

8 metrics

Shares disposed 85,951 shares Common Stock disposition to issuer on July 1, 2026

Shares after transaction 0 shares Total Stellar common stock held directly following transaction

Stock exchange ratio 0.3803 shares Prosperity common stock per share of Stellar common stock

Cash per share $11.36 Per Share Cash Merger Consideration for each Stellar share

Common stock included 66,891 shares Shares of Stellar Company Common Stock referenced in footnote

Restricted stock 6,757 shares Outstanding restricted stock awards that vested at the Effective Time

2024 performance unit awards 4,325 units Performance unit awards granted in 2024

2025 and 2026 performance units 5,123 and 2,855 units Performance unit awards granted in 2025 and 2026

Key Terms

Per Share Merger Consideration, Exchange Ratio, Agreement and Plan of Merger, restricted stock award, +2 more

6 terms

Per Share Merger Consideration financial

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

Exchange Ratio financial

"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.

Agreement and Plan of Merger regulatory

"transactions contemplated by the Agreement and Plan of Merger (the "Merger Agreement"),"

An Agreement and Plan of Merger is a formal document where two companies agree to combine into one, outlining how the process will happen. It’s like a step-by-step plan for merging, and it matters because it shows both sides have agreed on the details before the official transition takes place.

restricted stock award financial

"each outstanding restricted stock award in respect of Company Common Stock"

A restricted stock award is company shares given to an employee or executive that cannot be sold or fully owned until certain conditions—like staying with the company for a set time or hitting performance targets—are met. Think of it as a gift that only becomes yours after you fulfill specific obligations; for investors, these awards matter because they can increase the total shares outstanding when they vest, reveal how management is being paid and motivated, and create potential selling pressure when restrictions lift.

performance unit award financial

"each, a "performance unit award") fully vested and was converted"

Per Share Cash Merger Consideration financial

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/01/2026 - 07:40 AM Accepted by SEC EDGAR 07/01/2026 - 07:40 AM Learn about SEC filing dates

FAQ

What insider transaction did Stellar Bancorp (STEL) report for Akin Okan I.?

Stellar Bancorp reported that Senior Executive VP and CRO Akin Okan I. disposed of 85,951 shares of Stellar common stock to the issuer. The disposition was tied to the completion of Stellar’s merger into Prosperity Bancshares at a zero stated transaction price per share.

How were Stellar Bancorp (STEL) shares treated in the Prosperity merger?

Each share of Stellar Bancorp common stock was cancelled and converted into the right to receive 0.3803 shares of Prosperity common stock plus $11.36 in cash. This combined stock-and-cash package is referred to as the Per Share Merger Consideration for Stellar shareholders at the effective time.

What happened to Akin Okan I.’s restricted stock in Stellar Bancorp (STEL)?

Footnotes state that 6,757 restricted shares of Stellar common stock vested at the effective time of the Prosperity merger. These service-based awards were converted into the right to receive the same Per Share Merger Consideration as regular Stellar shares, without interest, under the merger terms.

How were Stellar Bancorp (STEL) performance unit awards treated in the merger?

Performance unit awards granted in 2024, 2025 and 2026 fully vested at the effective time. Each such award was converted into cash equal to the Per Share Merger Consideration value multiplied by the covered shares, with performance deemed achieved at 100% of target, or 200% for 2024 grants.

What were Akin Okan I.’s share holdings after the Stellar Bancorp (STEL) transaction?

After the reported disposition, Akin Okan I.’s direct holdings of Stellar Bancorp common stock were shown as zero shares. This reflects the cancellation of Stellar shares upon consummation of the merger and their conversion into rights to receive Prosperity stock and cash consideration.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Akin Okan I.

(Last) (First) (Middle)

9 GREENWAY PLAZA, SUITE 110

(Street)

HOUSTON TEXAS 77046

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Stellar Bancorp, Inc. [ STEL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Senior Executive VP, CRO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	07/01/2026		D		85,951	D	$0(1)(2)(3)	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Includes 66,891 shares of Company Common Stock (as defined below). On July 1, 2026 (the "Effective Time"), upon consummation of the transactions contemplated by the Agreement and Plan of Merger (the "Merger Agreement"), dated as of January 27, 2026, by and between Prosperity Bancshares, Inc., a Texas corporation ("Prosperity") and Stellar Bancorp, Inc., a Texas corporation (the "Company"), and subject to the terms and conditions set forth in the Merger Agreement, each share of the Company's common stock, par value $0.01 per share, ("Company Common Stock") outstanding immediately prior to the Effective Time was cancelled and 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") and (ii) an amount in cash equal to $11.36 (the "Per Share Cash Merger Consideration") ((i) and (ii) together, the "Per Share Merger Consideration").

2. Includes 6,757 shares of restricted stock. At the Effective Time, each outstanding restricted stock award in respect of Company Common Stock subject solely to service-based vesting, repurchase or other lapse restriction vested and was converted into the right to receive (without interest) the Per Share Merger Consideration.

3. Includes (a) 4,325 performance unit awards (as defined below) granted in 2024, (b) 5,123 performance unit awards granted in 2025, and (c) 2,855 performance unit awards granted in 2026. At the Effective Time, each outstanding restricted unit award in respect of Company 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 Company Common Stock subject to such performance unit award, with applicable performance-based vesting conditions 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).

	/s/ Justin M. Long, attorney-in-fact	07/01/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)