Vanguard Capital Management (WTM) discloses 127,993 shares, 5.18%

Rhea-AI Filing Summary

White Mountains Insurance Group Ltd was reported as having 127,993 shares beneficially owned by Vanguard Capital Management, representing 5.18% of the class as disclosed on a Schedule 13G. The filing states Vanguard Capital Management has sole dispositive power over 127,993 shares and sole voting power over 18,836 shares. The filing is signed by Ashley Grim on 04/30/2026 and includes a statement that ownership includes shares held for Vanguard funds and managed accounts.

Insights

Corporate Governance Analyst

Disclosure shows an institutional holder above the 5% threshold with dispositive control.

Vanguard Capital Management reports 127,993 shares beneficially owned (5.18%), with sole dispositive power and partial sole voting power of 18,836 shares. The filing follows Schedule 13G conventions for passive/investment managers.

Ownership is attributed to Vanguard funds and managed accounts; subsequent filings would show changes in position. Cash‑flow treatment and sale intentions are not stated in the excerpt.

Key Figures

Beneficially owned: 127,993 shares Percent of class: 5.18% Sole voting power: 18,836 shares +2 more

5 metrics

Beneficially owned 127,993 shares reported on Schedule 13G (cover date <date>03/31/2026</date>)

Percent of class 5.18% percent of class as stated on the filing

Sole voting power 18,836 shares number of shares with sole power to vote

Sole dispositive power 127,993 shares number of shares with sole power to dispose

Signature date 04/30/2026 signed by Ashley Grim, Head of Global Fund Administration

Key Terms

Schedule 13G, beneficially owned, dispositive power

3 terms

Schedule 13G regulatory

"Item 1. | (a) | Name of issuer: White Mountains Insurance Group Ltd"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 127993"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

dispositive power financial

"Item 4. | (iii) Sole power to dispose or to direct the disposition of: 127993"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

White Mountains Insurance Group Ltd

(Name of Issuer)

Common Stock

(Title of Class of Securities)

G9618E107

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): G9618E107

1

Names of Reporting Persons

Vanguard Capital Management

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 18,836.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 127,993.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

127,993.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.18 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Capital Management LLC and the following affiliates of Vanguard Capital Management LLC or business divisions of such affiliates: Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC and Vanguard Investments Australia Ltd. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Capital Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Capital Management LLC, or business divisions of such subsidiaries, whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: White Mountains Insurance Group Ltd
(b)	Address of issuer's principal executive offices: 80 South Main Street, Hanover, NH, 03755
Item 2.
(a)	Name of person filing: Vanguard Capital Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): G9618E107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 127993
(b)	Percent of class: 5.18 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 18836
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 127993
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Vanguard Capital Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Vanguard Capital Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/30/2026

FAQ

What does Vanguard Capital Management report for WTM holdings?

Vanguard Capital Management reports 127,993 shares beneficially owned of WTM, representing 5.18%. The filing notes dispositive power over these shares and sole voting power for 18,836 shares.

Does Vanguard exercise voting or dispositive power over the WTM shares?

Yes. The filing states Vanguard has sole dispositive power over 127,993 shares and sole voting power over 18,836 shares, with no shared voting or dispositive power disclosed.

When was the Schedule 13G for WTM signed?

The Schedule 13G was signed by Ashley Grim, Head of Global Fund Administration, on 04/30/2026. The cover indicates holdings as reported on the form dated 03/31/2026.

Is the reported ownership held on behalf of other Vanguard entities?

Yes. The filing explains the shares include holdings for Vanguard funds and managed accounts and lists affiliated divisions such as Vanguard Asset Management Limited and Vanguard Global Advisers, LLC.

Does the filing state Vanguard will sell or buy WTM shares?

No. The Schedule 13G excerpt discloses beneficial ownership and voting/dispositive powers but does not state any intent to buy or sell or describe planned transactions.