White Mountains (WTM) director files insider sale of 5,000 shares

Rhea-AI Filing Summary

White Mountains Insurance Group Ltd director reported a stock sale of company shares. On 12/19/2025, the reporting person sold 5,000 common shares in a transaction coded "S" (sale) at a price of $2,050 per share. After this sale, the director beneficially owned 10,440 common shares directly. In addition, 119 common shares were held indirectly through a 401(k) plan. The filing is submitted as a Form 4/A amendment for an earlier report dated 12/22/2025 and reflects the director’s updated ownership position.

Insider Trade Summary

Net Seller: 5,000 shares ($10,250,000)

Net Sell 2 txns

Insider CAMPBELL REID TARLTON

Role Director

Sold 5,000 shs ($10.25M)

Type	Security	Shares	Price	Value
Sale	Common Shares	5,000	$2,050.00	$10.25M
holding	Common Shares	--	--	--

Holdings After Transaction: Common Shares — 10,440 shares (Direct); Common Shares — 119 shares (Indirect, by 401(k))

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

Accepted by SEC EDGAR 12/22/2025 - 04:51 PM Learn about SEC filing dates

FAQ

What insider transaction did WHITE MOUNTAINS INSURANCE GROUP LTD (WTM) report?

The filing reports that a director of White Mountains Insurance Group Ltd sold 5,000 common shares in a transaction coded "S" (sale) on 12/19/2025.

At what price were the WTM shares sold in this insider transaction?

The 5,000 common shares were sold at a price of $2,050 per share, as disclosed in the transaction details.

How many WHITE MOUNTAINS (WTM) shares does the director own after the sale?

Following the reported sale, the director beneficially owned 10,440 common shares directly and 119 common shares indirectly through a 401(k) plan.

What is the relationship of the reporting person to WHITE MOUNTAINS INSURANCE GROUP LTD (WTM)?

The reporting person is identified as a Director of White Mountains Insurance Group Ltd on the ownership form.

Is this WHITE MOUNTAINS INSURANCE GROUP LTD (WTM) insider filing an amendment?

Yes. The document is a Form 4/A amendment, referencing an original filing date of 12/22/2025.

Does the filing show any derivative securities for the WTM insider?

The section for derivative securities is included but does not list any specific derivative transactions or holdings for this reporting person.

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^*

CAMPBELL REID TARLTON

(Last) (First) (Middle)

C/O WHITE MOUNTAINS INSURANCE GROUP, LTD

23 SOUTH MAIN STREET, SUITE 3B

(Street)

HANOVER NH 03755

(City) (State) (Zip)

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)

3. Date of Earliest Transaction (Month/Day/Year)
12/19/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)
12/22/2025

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

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

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	12/19/2025		S		5,000	D	$2,050	10,440	D
Common Shares								119	I	by 401(k)

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:

	Wesley C Bell, by Power of Attorney	12/22/2025
	** 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.