# EDGAR Filing Document

**Accession Number:** 0000776867
**File Stem:** 0001628280-26-012417
**Filing Date:** 2026-2
**Character Count:** 9626
**Document Hash:** 684ad0fb2f1e833454bfadb4fdeab660
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-012417.hdr.sgml**: 20260226

**ACCESSION NUMBER**: 0001628280-26-012417

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20260226

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260226

**DATE AS OF CHANGE**: 20260226

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** WHITE MOUNTAINS INSURANCE GROUP LTD
- **CENTRAL INDEX KEY:** 0000776867
- **STANDARD INDUSTRIAL CLASSIFICATION:** FIRE, MARINE & CASUALTY INSURANCE [6331]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 942708455
- **STATE OF INCORPORATION:** D0
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-08993
- **FILM NUMBER:** 26690578

**BUSINESS ADDRESS:**
- **STREET 1:** 23 SOUTH MAIN STREET
- **STREET 2:** SUITE 3B
- **CITY:** HANOVER
- **STATE:** NH
- **ZIP:** 03755
- **BUSINESS PHONE:** 603 640 2200

**MAIL ADDRESS:**
- **STREET 1:** 23 SOUTH MAIN STREET
- **STREET 2:** SUITE 3B
- **CITY:** HANOVER
- **STATE:** NH
- **ZIP:** 03755

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** WHITE MOUNTAINS INSURANCE GROUP INC
- **DATE OF NAME CHANGE:** 19990603

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FUND AMERICAN ENTERPRISES HOLDINGS INC
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FUND AMERICAN COMPANIES INC
- **DATE OF NAME CHANGE:** 19920701

?xml version='1.0' encoding='ASCII'? wtm-20260226

**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**

**February 26, 2026**

Date of Report (Date of earliest event reported)

**WHITE MOUNTAINS INSURANCE GROUP, LTD.**

(Exact name of registrant as specified in its charter)

---

| | | |
|:---|:---|:---|
| **Bermuda** <br>(State or other jurisdiction of<br> incorporation or organization) | **1-8993**<br>(Commission file number) | **94-2708455**<br>(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).&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 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. &nbsp;&nbsp;&nbsp;&nbsp; □

------

**ITEM 8.01. OTHER EVENTS.**

On February 26, 2026, White Mountains Insurance Group, Ltd. (NYSE: WTM) ("White Mountains"), RedBird Capital Partners ("RedBird"), and Bishop Street Underwriters ("Bishop Street") issued a joint press release announcing that White Mountains has completed a $125 million structured capital investment into Bishop Street. Bishop Street, a RedBird portfolio company, is a diversified platform of MGAs and niche underwriting teams focused on the property and casualty insurance sector. A copy of the joint press release is attached as Exhibit 99.1 to this report.

**ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS.**

(d) Exhibits

99.1 [Press Release, dated February 26, 2026](wtmexhibit991bishopstreet.htm)

------

**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. | WHITE MOUNTAINS INSURANCE GROUP, LTD. |
| February 26, 2026 | By: | <u>/s/ MICHAELA J. HILDRETH</u> <br>&nbsp;&nbsp;&nbsp;&nbsp; Michaela J. Hildreth <br>*&nbsp;&nbsp;&nbsp;&nbsp; Managing Director and* <br>*&nbsp;&nbsp;&nbsp;&nbsp; Chief Accounting Officer*  |

---

## Exhibit 99.1

**Exhibit 99.1**

**Bishop Street Underwriters Announces Strategic Investment by White Mountains**

Strategic Investment to Support and Accelerate Growth

**NEW YORK, NY, February 26, 2026 –** Bishop Street Underwriters ("Bishop Street"), a RedBird Capital Partners portfolio company, today announced that it has completed a strategic structured capital investment of $125 million by White Mountains Insurance Group, Ltd. ("White Mountains") (NYSE: WTM).

"We are thrilled to welcome White Mountains as a strategic growth partner during a period of unprecedented momentum," said Chad Levine, Chief Executive Officer of Bishop Street Underwriters. "Bishop Street's 2025 performance - surpassing $650 million in gross written premium and industry leading organic growth while maintaining a stellar sub-50 percent portfolio loss ratio - validates our commitment to backing elite underwriters, pursuing accretive acquisitions and launching de novo programs. With the addition of White Mountains as a strategic partner, we will look to accelerate our strategy and cement our global footprint in 2026."

Chad Weber, President of Bishop Street Underwriters, added "White Mountains brings a formidable history of scaling successful MGAs, a deep-seated knowledge of the MGA landscape and an understanding of the intricacies of our industry. We are excited to welcome their expertise to our boardroom and leverage their capabilities and connectivity to unlock new opportunities for the platform and our operating partners."

Liam Caffrey, Chief Executive Officer of White Mountains, said, "Bishop Street is quickly emerging as an industry-leading MGA platform. This is a talented executive team with a strong track record of scaling insurance distribution businesses. We believe Bishop Street is well positioned to capitalize on secular growth tailwinds." Chris Delehanty, Head of M&A of White Mountains added, "We are pleased to partner with RedBird and a team we've known for many years. We look forward to collaborating on opportunities to accelerate the company's growth and performance."

Mike Zabik, Partner at RedBird Capital Partners, said, "White Mountains is a long-term investor, with deep insurance expertise, an outstanding track record and relevant resources to make them the ideal partner for Bishop Street and RedBird. With an established global footprint and significant opportunities for growth and partnership, this investment and partnership will allow Bishop Street to capitalize on its growth objectives in 2026 and beyond."

**About Bishop Street Underwriters**

Bishop Street Underwriters, a RedBird Capital Partners portfolio company, seeks to partner with Managing General Agents ("MGAs") as well as niche underwriting teams. Bishop Street aims to combine their best-in-class (re)insurance executive team's vision with RedBird's strong track record, expertise and network in the financial services sector to build a differentiated platform that is uniquely positioned to capitalize on secular growth tailwinds in the industry. For more information, please go to <u>www.bishopstreetuw.com</u>.

------

**About White Mountains**

White Mountains is a Bermuda-domiciled financial services holding company traded on the New York Stock Exchange under the symbol WTM and on the Bermuda Stock Exchange under the symbol WTM.BH. Additional financial information and other items of interest are available at the Company's web site located at <u>www.whitemountains.com</u>.

**About RedBird Capital Partners**

RedBird Capital Partners is a private investment firm that builds high-growth companies and provides strategic capital solutions to founders and entrepreneurs. Founded in 2014 by Gerry Cardinale, RedBird integrates sophisticated private equity investing with a hands-on business building mandate, focusing on two core ecosystems – Sports, Media & Entertainment and Financial Services. The firm currently manages over $14 billion in assets on behalf of a global group of blue chip institutional and family office investors. For more information, please go to <u>www.redbirdcap.com</u>.

**Media Contacts**

**Bishop Street** 

Dan Gagnier

Gagnier Communications

<u>bishopstreet@gagnierfc.com</u> 

646.569.5897 <br>

**White Mountains**

Rob Seelig

<u>ir@whitemountains.com</u>

+1 (603) 640-2212

<br>