Whitestone REIT COO reports tax-withheld shares

Whitestone REIT President and COO Christine J. Mastandrea reported a routine share disposition related to taxes, not an open-market sale.

Rhea-AI Filing Summary

Whitestone REIT President and COO Christine J. Mastandrea reported a routine share disposition related to taxes, not an open-market sale. On June 30, 2026, 8,991 common shares were withheld by the company to cover tax obligations tied to the vesting of previously granted restricted units under the 2018 Long-Term Equity Incentive Ownership Plan. After this tax-withholding transaction, she directly holds 472,463 common shares of Whitestone REIT.

Insider Trade Summary

Exercise Price or Tax Liability: 8,991 shares

Exercise Price or Tax Liability 1 txn

Insider Mastandrea Christine J

Role President and COO

Type	Security	Shares	Price	Value
Exercise Price or Tax Liability	Common Shares	8,991	$18.96	$170K

Holdings After Transaction: Common Shares — 472,463 shares (Direct)

Footnotes (2)

1. F1. Represents common shares withheld by the Company to satisfy tax withholding obligations in connection with the vesting of certain restricted units previously granted pursuant to the Company's 2018 Long-Term Equity Incentive Ownership Plan.
2. F2. Per Share value assigned by the Company to the tax withholding shares based on the closing sales price of the common shares on June 30, 2026.

Key Figures

Shares withheld for taxes: 8,991 shares Per-share tax value: $18.96 per share Shares held after transaction: 472,463 shares

3 metrics

Shares withheld for taxes 8,991 shares Common shares withheld on June 30, 2026 for tax obligations

Per-share tax value $18.96 per share Value assigned based on June 30, 2026 closing price

Shares held after transaction 472,463 shares Direct common share holdings following tax-withholding disposition

Key Terms

tax withholding obligations, restricted units, 2018 Long-Term Equity Incentive Ownership Plan, closing sales price

4 terms

tax withholding obligations financial

"withheld by the Company to satisfy tax withholding obligations in connection with the vesting"

restricted units financial

"vesting of certain restricted units previously granted pursuant to the Company's 2018 Long-Term Equity Incentive Ownership Plan"

2018 Long-Term Equity Incentive Ownership Plan financial

"previously granted pursuant to the Company's 2018 Long-Term Equity Incentive Ownership Plan"

closing sales price financial

"based on the closing sales price of the common shares on June 30, 2026"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did Whitestone REIT (WSR) report for Christine J. Mastandrea?

Whitestone REIT reported that President and COO Christine J. Mastandrea had 8,991 common shares withheld by the company to satisfy tax obligations from vesting restricted units. This was a tax-withholding disposition, not an open-market share sale.

How many Whitestone REIT (WSR) shares were withheld for taxes in this Form 4?

The filing shows 8,991 Whitestone REIT common shares were withheld. These shares covered tax withholding obligations arising from the vesting of certain restricted units granted under the company’s 2018 Long-Term Equity Incentive Ownership Plan.

At what price were the Whitestone REIT (WSR) tax-withholding shares valued?

The withheld tax shares were valued at $18.96 per share. That value was assigned by the company based on the closing sales price of Whitestone REIT common shares on June 30, 2026, the date of the vesting event.

How many Whitestone REIT (WSR) shares does Christine J. Mastandrea hold after this transaction?

After the tax-withholding transaction, Christine J. Mastandrea directly holds 472,463 Whitestone REIT common shares. This post-transaction figure reflects her remaining direct ownership following the 8,991 shares withheld for tax obligations.

Was the Whitestone REIT (WSR) insider transaction an open-market sale?

No. The transaction was a tax-withholding disposition, not an open-market sale. Shares were withheld by Whitestone REIT to satisfy tax obligations triggered by the vesting of restricted units awarded under its 2018 long-term equity incentive plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 07/02/2026 - 06:45 PM EDT Learn about SEC filing dates

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

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)
06/30/2026

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	06/30/2026		F		8,991(1)	D	$18.96(2)	472,463	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. Represents common shares withheld by the Company to satisfy tax withholding obligations in connection with the vesting of certain restricted units previously granted pursuant to the Company's 2018 Long-Term Equity Incentive Ownership Plan.

2. Per Share value assigned by the Company to the tax withholding shares based on the closing sales price of the common shares on June 30, 2026.

	/s/ David K. Holeman Attorney-in Fact for Christine J. Mastandrea	07/02/2026
	** 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)