White Mountains (WTM) director receives 135-share annual equity award

Rhea-AI Filing Summary

Tanner David Allen reported acquisition or exercise transactions in this Form 4 filing.

WHITE MOUNTAINS INSURANCE GROUP LTD director David Allen Tanner received an equity grant of 135 common shares as an annual director share award. The shares were awarded at no cash cost per share and increased his direct holdings to 2,014 common shares following the transaction.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Tanner David Allen

Role null

Type	Security	Shares	Price	Value
Grant/Award	Common Shares	135	$0.00	--

Holdings After Transaction: Common Shares — 2,014 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Shares granted: 135 common shares Price per share: $0.00 per share Shares held after grant: 2,014 common shares

3 metrics

Shares granted 135 common shares Annual director share award on May 21, 2026

Price per share $0.00 per share Reported grant price for awarded shares

Shares held after grant 2,014 common shares Director’s direct holdings following the transaction

Key Terms

Annual Director Share Award, Common Shares, Grant, award, or other acquisition

3 terms

Annual Director Share Award financial

"Footnote describes the transaction as an "Annual Director Share Award""

Common Shares financial

"Security title for the reported transaction is listed as "Common Shares""

Common shares are the basic units of ownership in a company that give holders a claim on profits and a right to vote on key matters, like electing the board. Think of them as membership cards in a club: they let you share in successes and losses, but in a bankruptcy or liquidation they are paid after creditors and preferred shareholders, so their value can swing more and matters for assessing risk and potential return.

Grant, award, or other acquisition financial

"Transaction code A is described as "Grant, award, or other acquisition""

Form 4 Insider Transactions: What Each Field Means →

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^*

Tanner David Allen

(Last) (First) (Middle)

C/O WHITE MOUNTAINS INSURANCE GROUP, LTD

23 SOUTH MAIN STREET, SUITE 3B

(Street)

HANOVER NEW HAMPSHIRE 03755

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
WHITE MOUNTAINS INSURANCE GROUP LTD [ WTM ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/21/2026

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	05/21/2026		A		135(1)	A	$0	2,014	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. Annual Director Share Award

	Wesley C. Bell, by Power of Attorney	05/21/2026
	** 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)

FAQ

What insider transaction did WHITE MOUNTAINS (WTM) report for David Allen Tanner?

WHITE MOUNTAINS reported that director David Allen Tanner received a grant of 135 common shares as an annual director share award. This was a compensation-related equity grant, not an open-market purchase or sale, and involved no cash paid per share.

How many WHITE MOUNTAINS (WTM) shares does David Allen Tanner hold after this Form 4?

After the reported grant, David Allen Tanner directly holds 2,014 WHITE MOUNTAINS common shares. His holdings increased from the 135-share annual director share award, reflecting routine equity-based compensation rather than a market trade in the company’s stock.

Was the WHITE MOUNTAINS (WTM) Form 4 transaction a stock purchase or sale?

The Form 4 shows an acquisition coded as a grant or award, not a market purchase or sale. Tanner received 135 common shares at a reported price of $0.00 per share as compensation, described as an annual director share award, rather than buying or selling shares.

What does the footnote on the WHITE MOUNTAINS (WTM) Form 4 indicate?

The footnote describes the transaction as an “Annual Director Share Award.” This clarifies that the 135 common shares granted to director David Allen Tanner represent standard board compensation in stock, instead of a discretionary open-market investment decision or liquidity-driven sale.

Does the WHITE MOUNTAINS (WTM) Form 4 show any derivative or option exercises?

The filing does not report any derivative or option exercises. It lists only one non-derivative transaction: a grant of 135 common shares to director David Allen Tanner as an annual director share award, with no derivative positions shown in the derivative summary.