FALSE 0000776867 Bermuda 1-8993 94-2708455 03755☐☐☐☐☐0000776867 2025-06-06 2025-06-06
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
June 6, 2025
Date of Report (Date of earliest event reported)
WHITE MOUNTAINS INSURANCE GROUP, LTD.
(Exact name of registrant as specified in its charter)

Bermuda (State or other jurisdiction of incorporation or organization) | 1-8993 (Commission file number) | 94-2708455 (I.R.S. Employer Identification No.)

23 South Main Street, Suite 3B, Hanover, New Hampshire 03755
(Address of principal executive offices)
(603) 640-2200
(Registrant’s telephone number, including area code)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Securities registered pursuant to Section 12(b) of the Act:

Title of each class |  | Trading Symbol(s) |  | Name of each exchange on which registered
Common Shares, par value $1.00 per share |  | WTM |  | New York Stock Exchange
|  | WTM.BH |  | Bermuda Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933(§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

ITEM 7.01 Regulation FD Disclosure.
The Registrant’s executive officers intend to utilize the presentation furnished as Exhibit 99.1 to this Form 8-K, in whole or in part, at the Registrant’s Annual Investor Information Meeting to be held on June 6, 2025. The presentation is incorporated by reference herein.
The information in this report (including Exhibit 99.1) is being furnished pursuant to Item 7.01 and shall not be deemed to be filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise be subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act.
ITEM 9.01 Financial Statements and Exhibits.
(d) Exhibits. The following exhibit is furnished herewith:
EXHIBIT INDEX
99.1 Supplemental Regulation FD Disclosure.
2

SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

|  | WHITE MOUNTAINS INSURANCE GROUP, LTD. |
June 06, 2025 |  | By: | /s/ MICHAELA J. HILDRETH Michaela J. Hildreth Managing Director and Chief Accounting Officer |

3