Segment Information

6 Months Ended

Jun. 30, 2026

As of June 30, 2026, White Mountains conducted its operations through five reportable segments: (1) Ark/WM Outrigger, (2) Kudu, (3) HG Global, (4) Distinguished and (5) WTM Partners, with its remaining operating businesses, holding companies and other assets included in Other Operations. White Mountains has made its segment determination based on consideration of the following criteria: (i) the nature of the business activities of each of the Company’s subsidiaries and affiliates; (ii) the manner in which the Company’s subsidiaries and affiliates are organized; (iii) the existence of primary managers responsible for specific subsidiaries and affiliates; and (iv) the organization of information provided to the Company’s CODM and the Board of Directors. The Company’s CODM is its Chief Executive Officer. The CODM utilizes each segment’s pre-tax income (loss) in assessing each segment’s performance and allocating resources. Other measures of segment profitability are also reviewed by the CODM. Significant intercompany transactions among White Mountains’s segments have been eliminated herein.

White Mountains consolidates its segregated account of Outrigger Re Ltd., WM Outrigger Re, in its financial statements. WM Outrigger Re exclusively provides reinsurance protection to Ark, and WM Outrigger Re’s quota share reinsurance agreement with GAIL eliminates in White Mountains’s consolidated financial statements. As a result, WM Outrigger Re is aggregated with Ark within the Ark/WM Outrigger segment.

On September 2, 2025, White Mountains completed the Distinguished Transaction. As a result, White Mountains began consolidating Distinguished in its financial statements on September 2, 2025. See Note 2 — “Significant Transactions.”

In the second quarter of 2026, WTM Partners completed the acquisitions of Hawkeye Electric and Basesix. As a result, WTM Partners is presented as a separate reportable segment. The CODM assesses the performance of WTM Partners’s operating companies and allocates resources in the aggregate to the WTM Partners segment. Prior period amounts have been reclassified to conform to the current period’s presentation.

On December 5, 2025, White Mountains completed the Bamboo Sale Transaction. As a result, White Mountains deconsolidated the Bamboo Group on December 5, 2025, and Bamboo is no longer a reportable segment. Through December 5, 2025, Bamboo’s results of operations are presented within the Bamboo segment. White Mountains’s noncontrolling equity interest in the Bamboo SPV is accounted for at fair value in other long-term investments within Other Operations. See Note 2 — “Significant Transactions.”

The following tables present White Mountains’s pre-tax financial results by segment for the three and six months ended June 30, 2026 and 2025:


	Ark/WM Outrigger												Other Operations		Total
Millions	Ark		WM Outrigger Re		Kudu		HG Global		Distinguished		WTM Partners
Three Months Ended June 30, 2026
Earned insurance premiums (1)	$	375.4	$	.8	$	—	$	7.7	$	—	$	—	$	.7	$	384.6
Net investment income (2)	26.9		1.1		19.0		7.8		.6		—		15.5		70.9
Net realized and unrealized investment gains (losses) (2)	30.5		—		49.7		(2.0)		—		—		72.4		150.6
Net realized and unrealized investment gains (losses) from investment in MediaAlpha	—		—		—		—		—		—		58.4		58.4
Interest income from BAM Surplus Notes	—		—		—		6.9		—		—		—		6.9


Commission and fee revenues (1)	—		—		—		—		56.6		—		3.8		60.4
Product and services revenues	—		—		—		—		—		92.8		14.7		107.5
Other revenues (1) (2)	4.9		—		.2		—		.2		—		—		5.3
Total revenues	437.7		1.9		68.9		20.4		57.4		92.8		165.5		844.6
Loss and LAE (3)	175.7		(.1)		—		—		—		—		.1		175.7
Insurance acquisition expenses (3)	103.4		.3		—		2.1		—		—		.3		106.1

Cost of sales	—		—		—		—		—		72.6		7.5		80.1
Broker commission expenses	—		—		—		—		23.3		—		—		23.3
Amortization of other intangible assets (4)	—		—		—		—		6.4		1.3		.9		8.6
General and administrative expenses (3) (4) (5)	44.4		—		4.7		4.2		34.6		14.2		41.2		143.3
Change in fair value of contingent consideration	31.7		—		—		—		—		—		—		31.7
Interest expense	4.1		—		7.2		3.7		3.6		.6		.6		19.8
Total expenses	359.3		.2		11.9		10.0		67.9		88.7		50.6		588.6
Pre-tax income (loss)	$	78.4	$	1.7	$	57.0	$	10.4	$	(10.5)	$	4.1	$	114.9	$	256.0

(1) Other Operations’s earned insurance premiums and commission and fee revenues are included in other revenues in the consolidated statement of operations.

(2) Distinguished’s net investment income is included in other revenues in the consolidated statement of operations.

(3) Other Operations’s loss and LAE and insurance acquisition expenses are included in general and administrative expenses in the consolidated statement of operations.

(4) Amortization of other intangible assets is included in general and administrative expenses in the consolidated statement of operations.

(5) Ark’s general and administrative expenses include $36.3 of other underwriting expenses.


		Ark/WM Outrigger
Millions		Ark			WM Outrigger Re			Kudu			HG Global			WTM Partners			Bamboo			Other Operations			Total
Three Months Ended June 30, 2025
Earned insurance premiums (1)		$	357.1		$	7.1		$	—		$	7.1		$	—		$	1.6		$	2.3		$	375.2
Net investment income (2)		24.1			2.2			19.3			6.5			—			.7			8.6			61.4
Net realized and unrealized investment gains (losses) (2)	51.1			—			.8			3.1			—			—			31.8			86.8
Net realized and unrealized investment gains (losses) from investment in MediaAlpha		—			—			—			—			—			—			30.5			30.5
Interest income from BAM Surplus Notes		—			—			—			7.5			—			—			—			7.5
Commission and fee revenues (1)		—			—			—			—			—			59.1			4.2			63.3
Product and services revenues		—			—			—			—			42.8			—			13.5			56.3
Other revenues (1) (2)		6.3			—			.3			—			—			1.1			.5			8.2
Total revenues		438.6			9.3			20.4			24.2			42.8			62.5			91.4			689.2
Loss and LAE (3)		162.3			1.7			—			—			—			1.7			.8			166.5
Insurance acquisition expenses (3)		95.8			1.4			—			2.0			—			(.6)			.9			99.5
Cost of sales		—			—			—			—			35.2			—			7.2			42.4
Broker commission expenses		—			—			—			—			—			19.8			—			19.8
Amortization of other intangible assets (4)	—			—			.1			—			—			4.0			1.0			5.1
General and administrative expenses (3) (4) (5)		56.5			—			3.5			1.0			6.4			18.6			46.4			132.4
Change in fair value of contingent consideration		28.4			—			—			—			—			—			—			28.4
Interest expense		4.3			—			6.1			4.5			.3			2.9			.5			18.6
Total expenses		347.3			3.1			9.7			7.5			41.9			46.4			56.8			512.7
Pre-tax income (loss)		$	91.3		$	6.2		$	10.7		$	16.7		$	.9		$	16.1		$	34.6		$	176.5

(1) Other Operations’s earned insurance premiums and commission and fee revenues are included in other revenues in the consolidated statement of operations.

(2) Bamboo’s net investment income is included in other revenues in the consolidated statement of operations.

(3) Other Operations’s loss and LAE and insurance acquisition expenses are included in general and administrative expenses in the consolidated statement of operations.

(4) Amortization of other intangible assets is included in general and administrative expenses in the consolidated statement of operations.

(5) Ark’s general and administrative expenses include $46.3 of other underwriting expenses.


	Ark/WM Outrigger												Other Operations
Millions	Ark		WM Outrigger Re		Kudu		HG Global		Distinguished		WTM Partners				Total
Six Months Ended June 30, 2026
Earned insurance premiums (1)	$	746.5	$	3.5	$	—	$	15.4	$	—	$	—	$	4.1	$	769.5
Net investment income (2)	54.3		2.4		39.8		15.5		1.3		—		29.0		142.3
Net realized and unrealized investment gains (losses) (2)	(2.3)		(.1)		91.7		(7.2)		—		—		79.3		161.4
Net realized and unrealized investment gains (losses) from investment in MediaAlpha	—		—		—		—		—		—		(6.8)		(6.8)
Interest income from BAM Surplus Notes	—		—		—		13.8		—		—		—		13.8

Commission and fee revenues (1)	—		—		—		—		96.2		—		7.4		103.6
Product and services revenues	—		—		—		—		—		136.5		27.5		164.0
Net gain on sale of the Bamboo Group	—		—		—		—		—		—		2.4		2.4
Other revenues (1) (2)	11.6		—		.4		.1		.2		—		(.1)		12.2
Total revenues	810.1		5.8		131.9		37.6		97.7		136.5		142.8		1,362.4
Loss and LAE (3)	382.1		.2		—		—		—		—		.4		382.7
Insurance acquisition expenses (3)	201.3		1.2		—		4.2		—		—		1.6		208.3

Cost of sales	—		—		—		—		—		108.7		14.1		122.8
Broker commission expenses	—		—		—		—		40.5		—		—		40.5
Amortization of other intangible assets (4)	—		—		.1		—		13.8		2.5		1.9		18.3
General and administrative expenses (3) (4) (5)	91.9		—		8.8		4.9		64.4		22.8		85.7		278.5
Change in fair value of contingent consideration	41.7		—		—		—		—		—		—		41.7
Interest expense	8.2		—		14.3		7.3		7.1		.9		1.3		39.1
Total expenses	725.2		1.4		23.2		16.4		125.8		134.9		105.0		1,131.9
Pre-tax income (loss)	$	84.9	$	4.4	$	108.7	$	21.2	$	(28.1)	$	1.6	$	37.8	$	230.5

(1) Other Operations’s earned insurance premiums and commission and fee revenues are included in other revenues in the consolidated statement of operations.

(2) Distinguished’s net investment income is included in other revenues in the consolidated statement of operations.

(3) Other Operations’s loss and LAE and insurance acquisition expenses are included in general and administrative expenses in the consolidated statement of operations. (4) Amortization of other intangible assets is included in general and administrative expenses in the consolidated statement of operations.

(5) Ark’s general and administrative expenses include $71.2 of other underwriting expenses.


	Ark/WM Outrigger												Other Operations
Millions	Ark		WM Outrigger Re		Kudu		HG Global		WTM Partners		Bamboo				Total
Six Months Ended June 30, 2025
Earned insurance premiums (1)	$	703.1	$	19.1	$	—	$	15.3	$	—	$	16.5	$	16.2	$	770.2
Net investment income (2)	45.4		4.4		38.7		12.8		—		1.4		18.3		121.0
Net realized and unrealized investment gains (losses) (2)	80.7		(.1)		44.8		13.1		—		.3		34.6		173.4
Net realized and unrealized investment gains (losses) from investment in MediaAlpha	—		—		—		—		—		—		(6.1)		(6.1)
Interest income from BAM Surplus Notes	—		—		—		15.0		—		—		—		15.0
Commission and fee revenues (1)	—		—		—		—		—		103.3		8.1		111.4
Product and services revenues	—		—		—		—		42.8		—		27.1		69.9
Other revenues (1) (2)	8.5		—		.7		.1		—		2.4		.5		12.2
Total revenues	837.7		23.4		84.2		56.3		42.8		123.9		98.7		1,267.0
Loss and LAE (3)	375.6		21.9		—		—		—		12.6		18.2		428.3
Insurance acquisition expenses (3)	179.6		1.1		—		3.9		—		6.0		6.0		196.6
Cost of sales	—		—		—		—		35.2		—		14.7		49.9
Broker commission expenses	—		—		—		—		—		35.3		—		35.3
Amortization of other intangible assets (4)	—		—		.2		—		—		8.0		2.1		10.3
General and administrative expenses (3) (4) (5)	92.3		.1		7.4		1.6		9.4		34.6		77.8		223.2
Change in fair value of contingent consideration	38.1		—		—		—		—		—		—		38.1
Interest expense	8.5		—		12.5		9.1		.3		5.0		1.0		36.4
Total expenses	694.1		23.1		20.1		14.6		44.9		101.5		119.8		1,018.1
Pre-tax income (loss)	$	143.6	$	.3	$	64.1	$	41.7	$	(2.1)	$	22.4	$	(21.1)	$	248.9

(1) Other Operations’s earned insurance premiums and commission and fee revenues are included in other revenues in the consolidated statement of operations.

(2) Bamboo’s net investment income and net realized and unrealized investment gains (losses) are included in other revenues in the consolidated statement of operations.

(3) Other Operations’s loss and LAE and insurance acquisition expenses are included in general and administrative expenses in the consolidated statement of operations.

(4) Amortization of other intangible assets is included in general and administrative expenses in the consolidated statement of operations.

(5) Ark’s general and administrative expenses include $74.8 of other underwriting expenses.

The following tables present White Mountains’s revenues from external customers by country for three and six months ended June 30, 2026 and 2025:


	Three Months Ended June 30, 2026
Millions	United States		United Kingdom		Bermuda		Other		Total
Earned insurance premiums	$	.2	$	237.6	$	146.8	$	—	$	384.6
Commission and fee revenues	56.6		—		—		3.8		60.4
Product and service revenues	107.5		—		—		—		107.5
Total	$	164.3	$	237.6	$	146.8	$	3.8	$	552.5


	Three Months Ended June 30, 2025
Millions	United States		United Kingdom		Bermuda		Other		Total
Earned insurance premiums	$	1.6	$	229.0	$	144.6	$	—	$	375.2
Commission and fee revenues	59.1		—		—		4.2		63.3
Product and service revenues	56.3		—		—		—		56.3
Total	$	117.0	$	229.0	$	144.6	$	4.2	$	494.8


	Six Months Ended June 30, 2026
Millions	United States		United Kingdom		Bermuda		Other		Total
Earned insurance premiums	$	.4	$	468.8	$	300.3	$	—	$	769.5
Commission and fee revenues	96.2		—		—		7.4		103.6
Product and service revenues	164.0		—		—		—		164.0
Total	$	260.6	$	468.8	$	300.3	$	7.4	$	1,037.1


	Six Months Ended June 30, 2025
Millions	United States		United Kingdom		Bermuda		Other		Total
Earned insurance premiums	$	16.5	$	444.5	$	309.2	$	—	$	770.2
Commission and fee revenues	103.3		—		—		8.1		111.4
Product and service revenues	69.9		—		—		—		69.9
Total	$	189.7	$	444.5	$	309.2	$	8.1	$	951.5

The following table presents White Mountains’s balance sheet information by segment as of June 30, 2026 and December 31, 2025:


Millions Selected Balance Sheet Data	Ark/WM Outrigger		Kudu		HG Global			Distinguished		WTM Partners		Other Operations			Total
June 30, 2026
Total investments	$	3,725.5	$	1,459.0	$	749.3		$	79.4	$	.6	$	2,120.6	(1)	$	8,134.4
Total assets	$	7,570.2	$	1,496.9	$	1,216.6		$	744.8	$	434.9	$	2,303.3	(2) (3)	$	13,766.7
Total liabilities	$	5,864.0	$	467.4	$	549.3	(2)	$	332.2	$	183.3	$	118.5	(2) (3)	$	7,514.7
Redeemable noncontrolling interests	$	—	$	—	$	—		$	131.5	$	—	$	—		$	131.5
Total White Mountains’s common shareholders’ equity	$	1,234.7	$	885.4	$	687.3	(2)	$	205.1	$	195.8	$	2,180.0	(2)	$	5,388.3
Nonredeemable noncontrolling interests	$	471.5	$	144.1	$	(20.0)		$	76.0	$	55.8	$	4.8		$	732.2
December 31, 2025
Total investments	$	3,926.5	$	1,313.3	$	784.2		$	94.0	$	.5	$	2,205.4	(1)	$	8,323.9
Total assets	$	6,354.1	$	1,402.3	$	1,236.8		$	735.4	$	182.4	$	2,395.5	(2) (3)	$	12,306.5
Total liabilities	$	4,528.5	$	446.9	$	499.5	(2)	$	307.1	$	91.4	$	178.0	(2) (3)	$	6,051.4
Redeemable noncontrolling interests	$	—	$	—	$	—		$	131.5	$	—	$	—		$	131.5
Total White Mountains’s common shareholders’ equity	$	1,360.4	$	814.2	$	755.7	(2)	$	223.1	$	60.1	$	2,211.9	(2)	$	5,425.4
Nonredeemable noncontrolling interests	$	465.2	$	141.2	$	(18.4)		$	73.7	$	31.0	$	5.5		$	698.2

(1) Total investments as of June 30, 2026 and December 31, 2025 exclude $1.6 and $1.0 related to an Other Operating Business that was reclassified to assets held for sale. See Note 19 — “Held for Sale.”

(2) HG Global preferred dividends payable to White Mountains’s subsidiaries are eliminated in White Mountains’s consolidated financial statements. For segment reporting, the HG Global preferred dividends payable to White Mountains’s subsidiaries included within the HG Global segment are eliminated against the offsetting receivable included within Other Operations and therefore added back to White Mountains’s common shareholders’ equity within the HG Global segment. As of June 30, 2026 and December 31, 2025, the HG Global preferred dividends payable to White Mountains’s subsidiaries were $470.7 and $527.2.

(3) Amounts include held for sale balances. See Note 19 — “Held for Sale.”

- Definition

The entire disclosure for segment reporting.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-40

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-42

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-34

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-31

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-26C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-26B

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-15

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-21

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-21

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 48
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-48

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 18: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 19: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 20: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 21: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 22: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org/280/tableOfContent

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-26

+ Details