Whitestone REIT (WSR) COO exits position in $19-per-share merger

Rhea-AI Filing Summary

Whitestone REIT President and COO Christine J. Mastandrea reported equity transactions tied to a merger in which each common share was converted into $19.00 in cash. A total of 718,873 common shares, including 246,410 from vested TSR Unit Awards, were disposed to the issuer, leaving her with no Whitestone REIT shares and ending her reporting obligations after the company’s delisting and deregistration.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Mastandrea Christine J

Role President and COO

Type	Security	Shares	Price	Value
Grant/Award	Common Shares	246,410	$0.00	--
Disposition	Common Shares	718,873	$19.00	$13.66M

Holdings After Transaction: Common Shares — 718,873 shares (Direct)

Footnotes (1)

1. Pursuant to the Agreement and Plan of Merger, dated as of April 8, 2026 (the "Merger Agreement"), by and among Whitestone REIT (the "Company"), Whitestone REIT Operating Partnership, L.P., AREG Wizard Parent LP, AREG Wizard Intermediate LP, and AREG Wizard Operating Partnership LP, each common share of beneficial interest, par value $0.001 per share, of the Company (each, a "Company Common Share"), was converted into the right to receive $19.00 in cash payment (without interest and subject to any applicable withholding taxes). As a result of the Company Merger (as defined in the Merger Agreement), Reporting Person no longer beneficially owns, directly or indirectly, any Company Common Shares, and after giving effect to the Company's delisting and deregistration, will cease to have reporting obligations. Includes 246,410 shares in respect of restricted performance share unit awards (each, a "TSR Unit Award"). In accordance with the terms of the Merger Agreement, each TSR Unit Award that was outstanding as of immediately prior to the effective time of the Company Merger, automatically became fully vested, was cancelled, and was converted into the right to receive an amount in cash (without interest and subject to any applicable withholding taxes) equal to the product of (i) the per share merger consideration of $19.00 and (ii) the number of Company Common Shares that would have vested pursuant to the terms of the TSR Unit Award, assuming that any performance based vesting conditions applicable to such TSR Unit Award for any performance period that has not been completed as of the effective time of the Company Merger were achieved at the levels based on the greater of target or actual performance through the effective time of the Company Merger.

Key Figures

Common shares disposed: 718,873 shares Merger cash consideration: $19.00 per share TSR Unit Awards shares: 246,410 shares +1 more

4 metrics

Common shares disposed 718,873 shares Issuer disposition of common shares at $19.00 per share in the merger

Merger cash consideration $19.00 per share Cash paid for each Whitestone REIT common share in the Company Merger

TSR Unit Awards shares 246,410 shares Shares underlying restricted performance share unit awards that became fully vested and converted to cash

Post-transaction holdings 0 shares Common shares beneficially owned by Christine J. Mastandrea after the Company Merger

Key Terms

Agreement and Plan of Merger, Company Merger, restricted performance share unit awards, TSR Unit Award, +1 more

5 terms

Agreement and Plan of Merger regulatory

"Pursuant to the Agreement and Plan of Merger, dated as of April 8, 2026"

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.

Company Merger regulatory

"As a result of the Company Merger, Reporting Person no longer beneficially owns"

restricted performance share unit awards financial

"Includes 246,410 shares in respect of restricted performance share unit awards"

TSR Unit Award financial

"each, a "TSR Unit Award"). In accordance with the terms of the Merger"

delisting and deregistration regulatory

"after giving effect to the Company's delisting and deregistration, will cease"

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/15/2026 - 04:10 PM Accepted by SEC EDGAR 07/15/2026 - 04:10 PM Learn about SEC filing dates

FAQ

What insider transactions did Whitestone REIT (WSR) report for President and COO Christine J. Mastandrea?

Christine J. Mastandrea reported 718,873 Whitestone REIT common shares disposed to the issuer at $19.00 per share in connection with a merger, including 246,410 shares from vested TSR Unit Awards, leaving her with no remaining Whitestone REIT shares.

At what price were Whitestone REIT (WSR) common shares converted in the merger?

Each Whitestone REIT common share was converted into the right to receive $19.00 in cash, without interest and subject to applicable withholding taxes, under the Agreement and Plan of Merger referenced in the insider report for President and COO Christine J. Mastandrea.

How many Whitestone REIT (WSR) shares did Christine J. Mastandrea ultimately dispose of?

Christine J. Mastandrea disposed of 718,873 common shares of Whitestone REIT to the issuer at $19.00 per share in the merger, resulting in her no longer beneficially owning, directly or indirectly, any Whitestone REIT common shares after the transaction.

What are the 246,410 TSR Unit Awards referenced for Whitestone REIT (WSR)?

The 246,410 shares relate to restricted performance share unit awards, called TSR Unit Awards. At the merger’s effective time, these awards became fully vested, were cancelled, and were converted into cash based on the $19.00 per share merger consideration and specified performance assumptions.

Does Christine J. Mastandrea still own Whitestone REIT (WSR) shares after the merger?

No. Following the Company Merger, Christine J. Mastandrea no longer beneficially owns any Whitestone REIT common shares, directly or indirectly. The filing notes that, after the company’s delisting and deregistration, she will cease to have ongoing SEC reporting obligations for these securities.

Why will Whitestone REIT (WSR) President and COO Christine J. Mastandrea cease to have reporting obligations?

She will cease to have reporting obligations because, after the Company Merger, she no longer beneficially owns any common shares, and the company is undergoing delisting and deregistration, eliminating the requirement for her to continue filing insider ownership reports for Whitestone REIT.

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^*

Mastandrea Christine J

(Last) (First) (Middle)

2600 SOUTH GESSNER

SUITE 500

(Street)

HOUSTON TEXAS 77063

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Whitestone REIT [ WSR ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and COO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/14/2026

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 Shares(1)	07/14/2026		A		246,410(2)	A	$0	718,873	D
Common Shares(1)	07/14/2026		D		718,873(2)	D	$19	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. Pursuant to the Agreement and Plan of Merger, dated as of April 8, 2026 (the "Merger Agreement"), by and among Whitestone REIT (the "Company"), Whitestone REIT Operating Partnership, L.P., AREG Wizard Parent LP, AREG Wizard Intermediate LP, and AREG Wizard Operating Partnership LP, each common share of beneficial interest, par value $0.001 per share, of the Company (each, a "Company Common Share"), was converted into the right to receive $19.00 in cash payment (without interest and subject to any applicable withholding taxes). As a result of the Company Merger (as defined in the Merger Agreement), Reporting Person no longer beneficially owns, directly or indirectly, any Company Common Shares, and after giving effect to the Company's delisting and deregistration, will cease to have reporting obligations.

2. Includes 246,410 shares in respect of restricted performance share unit awards (each, a "TSR Unit Award"). In accordance with the terms of the Merger Agreement, each TSR Unit Award that was outstanding as of immediately prior to the effective time of the Company Merger, automatically became fully vested, was cancelled, and was converted into the right to receive an amount in cash (without interest and subject to any applicable withholding taxes) equal to the product of (i) the per share merger consideration of $19.00 and (ii) the number of Company Common Shares that would have vested pursuant to the terms of the TSR Unit Award, assuming that any performance based vesting conditions applicable to such TSR Unit Award for any performance period that has not been completed as of the effective time of the Company Merger were achieved at the levels based on the greater of target or actual performance through the effective time of the Company Merger.

	/s/ David K. Holeman Attorney-in-Fact for Christine J. Mastandrea	07/15/2026
	** 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)