WHITE MOUNTAINS INSURANCE GROUP LTD

On September 2, 2025, White Mountains acquired a controlling financial interest in Distinguished (the “Distinguished Transaction”). See Note 2 — “Significant Transactions”on page F-19.

Distinguished is a full-service MGA and program administrator for specialty property and casualty insurance. Distinguished places insurance across a diversified portfolio of programs broadly grouped into two verticals. The ScaleCo vertical consists of established programs, primarily focused on real estate and hospitality end markets. The GrowthCo vertical consists of start-up programs, focused on a diversified set of specialty property and casualty insurance products across multiple industries. On behalf of its insurance carrier partners, Distinguished typically manages all aspects of the placement process, including product development, marketing, underwriting and policy issuance. Distinguished earns commissions based on the volume and profitability of the insurance that it places. Distinguished does not retain insurance risk.

As of December 31, 2025, White Mountains reported $735 million of total assets and $428 million of total equity related to Distinguished. As of December 31, 2025, White Mountains owned 55.5% of the basic units outstanding of Distinguished (43.6% on a fully-diluted/fully-converted basis, taking account of management’s equity incentives) and reported $132 million of redeemable noncontrolling interests and $74 million of nonredeemable noncontrolling interests related to Distinguished.

Marketing and Distribution

Distinguished is an MGA and program administrator with delegated binding authorities, and as such, is generally dependent on its carrier partners to bear the insurance risk on the programs designed and underwritten by Distinguished. Distinguished typically expands its programs when market conditions are attractive and shrinks its programs when market conditions are challenging. This practice has led to longstanding insurance carrier partner relationships, in some cases over 20 years. The insurance risk for Distinguished’s programs is supported by 17 insurance carrier partners, with the top three of these carrier partners accounting for 61% of Distinguished’s managed premiums for the year ended December 31, 2025, which includes periods prior to White Mountains’s ownership. White Mountains believes this information is useful in understanding the overall diversification in Distinguished’s capacity.

Distinguished primarily relies on third-party agents and brokers as its sales channel. Substantially all of Distinguished’s products are distributed through third-party agents and brokers who have the principal relationships with policyholders. Agents and brokers have significant influence over renewals, and thus Distinguished’s business model is dependent on its relationships with, and the success of, the agents and brokers with whom Distinguished does business. Distinguished’s programs are supported by over 2,000 agents and brokers, with the top three firms accounting for 10% of Distinguished’s managed premiums for the year ended December 31, 2025, which includes periods prior to White Mountains’s ownership. White Mountains believes this information is useful in understanding the overall diversification in Distinguished’s distribution base.

Competition

Distinguished operates in a highly competitive property and casualty insurance intermediary industry. Competitors are differentiated based on price, conditions of coverage, loss ratio performance, quality of service, technology and other factors. Distinguished’s primary competitors are typically specialty insurance distribution and underwriting businesses and their agents.

Managed Premiums and Commission and Fee Revenues

Managed premiums, which represent the total premiums placed by Distinguished, were $188 million for the period from September 2, 2025, the date of acquisition, through December 31, 2025. The following table presents Distinguished’s managed premiums and commission and fee revenues by vertical for the period from September 2, 2025 through December 31, 2025.

For the year ended December 31, 2025, Distinguished’s total managed premiums were $568 million, which increased 6% compared to the year ended December 31, 2024. This includes periods prior to White Mountains’s ownership of Distinguished, which White Mountains believes is useful in understanding the overall size and growth in Distinguished’s premium base.