8-K

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

September 8, 2021

Date of Report (Date of earliest event reported)

WHITE MOUNTAINS INSURANCE GROUP, LTD.

(Exact name of registrant as specified in its charter)

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:

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 8.01    Other Events.

On September 8, 2021, Group Ark Insurance Limited, a wholly owned subsidiary of Ark Insurance Holdings Limited (“Ark”) and a subsidiary of White Mountains Insurance Group, Ltd. (“White Mountains”), issued $70.0 million of floating rate subordinated notes due in 2041 (the “Notes”) via a private placement. The Notes qualify as Tier 2 capital under Bermuda’s solvency capital regime. The Notes are in addition to the previously disclosed €39.1 million of notes issued on July 13, 2021 and the $47.0 million of notes issued on August 11, 2021. In connection with the issuance of the Notes, White Mountains and Ark have terminated White Mountains’s commitment to provide up to $200.0 million of additional capital to Ark at Ark’s option.

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.

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