Loss and LAE reserves are typically comprised of case reserves for claims reported and reserves for losses that have occurred but for which claims have not yet been reported, referred to as IBNR reserves. IBNR reserves include a provision for expected future development on case reserves. Case reserves are estimated based on the experience and knowledge of claims staff regarding the nature and potential cost of each claim and are adjusted as additional information becomes known or payments are made. IBNR reserves are derived by subtracting paid loss and LAE and case reserves from estimates of ultimate loss and LAE. Actuaries estimate ultimate loss and LAE using various generally accepted actuarial methods applied to known losses and other relevant information. Like case reserves, IBNR reserves are adjusted as additional information becomes known or payments are made. Loss and LAE reserves are recognized within White Mountains’s P&C Insurance and Reinsurance, Financial Guarantee, P&C Insurance Distribution and certain Other Operations businesses.

Ark establishes loss and LAE reserves that are estimates of amounts needed to pay claims and related expenses in the future for insured events that have already occurred. Ark’s process of estimating reserves involves a considerable degree of judgment by management and, as of any given date, is inherently uncertain.

WM Outrigger Re entered into a quota share agreement with GAIL to provide collateralized reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. Ark renewed its quota share reinsurance agreement with WM Outrigger Re for the 2024 and 2025 underwriting years. WM Outrigger Re’s quota share reinsurance agreement with GAIL, including its loss and LAE reserves, eliminates in White Mountains’s consolidated financial statements.

Loss and LAE are categorized by the year in which the policy is underwritten (the year of account, or underwriting year) for purposes of Ark’s claims management and estimation of the ultimate loss and LAE reserves. For purposes of Ark’s reporting under GAAP, loss and LAE are categorized by the year in which the claim is incurred (the accident year).

Ultimate loss and LAE are generally determined by extrapolation of claims emergence and settlement patterns observed in the past that can reasonably be expected to persist into the future. In forecasting ultimate loss and LAE for any line of business, past experience with respect to that line of business is the primary resource, but cannot be relied upon in isolation. Ark’s own experience, particularly claims development experience, such as trends in case reserves, payments on and closings of claims, as well as changes in business mix and coverage limits, is the most important information for estimating its loss and LAE reserves. External data, available from organizations such as the Lloyd’s Market Association, consulting firms and other insurance and reinsurance companies, is used to supplement or corroborate Ark’s own experience. External data can be especially useful for estimating costs on newer lines of business. Ultimate loss and LAE for major losses and catastrophes are estimated based on the known and expected exposures to the loss event, rather than simply relying on the extrapolation of reported and settled claims.

For some lines of business, such as long-tail coverages discussed below, claims data reported in the most recent years of account are often too limited to provide a meaningful basis for analysis due to the typical delay in reporting and settling of claims. For this type of business, Ark uses an expected loss ratio method for the initial years of account. This is a standard and accepted actuarial reserve estimation method in these circumstances in which the loss ratio is selected based upon information used in pricing policies for that line of business, as well as any publicly available industry data, such as industry pricing, experience and trends.

Uncertainties in estimating ultimate loss and LAE are magnified by the time lag between when a claim actually occurs and when it is reported and eventually settled. This time lag is sometimes referred to as the “claim-tail.” The claim-tail for reinsurance and insurance obtained through brokers, MGAs and reinsurance intermediaries (collectively, the “insurance and reinsurance intermediaries”) is further extended because claims are first reported to either the original primary insurance company or the insurance and reinsurance intermediaries. The claim-tail for most property coverages is typically short (usually a few days up to a few months). Settlements for casualty/liability coverages can extend for long periods of time as claims are often reported and ultimately paid or settled years after the related loss events occur. During the long claims reporting and settlement period, additional facts regarding coverages written in prior years of account, as well as about actual claims and trends, may become known and, as a result, Ark may adjust its reserves. The inherent uncertainties of estimating loss and LAE reserves are increased by the diversity of loss development patterns among different types of reinsurance treaties, facultative contracts or direct insurance contracts, the necessary reliance on the ceding companies and insurance and reinsurance intermediaries for information regarding reported claims and the differing reserving practices among ceding companies and insurance and reinsurance intermediaries.

If management determines that an adjustment is appropriate, the adjustment is booked in the accounting period in which such determination is made. Accordingly, should reserves need to be increased or decreased in the future from amounts currently established, future results of operations would be negatively or positively impacted.

In determining ultimate loss and LAE, the cost to indemnify claimants, provide needed legal defense and other services for insureds and administer the investigation and adjustment of claims are considered. These claims costs are influenced by many factors that change over time, such as expanded coverage definitions as a result of new court decisions, inflation in costs to repair or replace damaged property, inflation in the cost of medical services and legislated changes in statutory benefits, as well as by the unique facts that pertain to each claim. As a result, the rate at which claims arose in the past and the costs to settle them may not always be representative of what will occur in the future. The factors influencing changes in claims costs are often difficult to isolate or quantify and developments in paid and incurred losses from historical trends are frequently subject to multiple and conflicting interpretations. Changes in coverage terms or claims handling practices may also cause future experience and/or development patterns to vary from the past. A key objective of actuaries in developing estimates of ultimate loss and LAE and resulting IBNR reserves is to identify aberrations and systemic changes occurring within historical experience and accurately adjust for them so that the future can be projected more reliably. Because of the factors previously discussed, this process requires the use of informed judgment and is inherently uncertain.

Ark performs an actuarial review of its recorded loss and LAE reserves each quarter, using several generally accepted actuarial methods to evaluate its loss reserves, each of which has its own strengths and weaknesses. Management places more or less reliance on a particular method based on the facts and circumstances at the time the reserve estimates are made. These methods generally fall into one of the following categories or are hybrids of one or more of the following categories:

•Historical paid loss development methods: These methods use historical loss payments over discrete periods of time to estimate future losses. Historical paid loss development methods assume that the ratio of losses paid in one period to losses paid in an earlier period will remain constant. These methods necessarily assume that factors that have affected paid losses in the past, such as inflation or the effects of litigation, will remain constant in the future. Because historical paid loss development methods do not use case reserves to estimate ultimate losses, they can be more reliable than the other methods discussed below that look to case reserves (such as actuarial methods that use incurred losses) in situations where there are significant changes in how case reserves are established by a company’s claims adjusters. However, historical paid loss development methods are more leveraged, meaning that small changes in payments have a larger impact on estimates of ultimate losses, than actuarial methods that use incurred losses because cumulative loss payments take much longer to approach the expected ultimate losses than cumulative incurred amounts. In addition, and for similar reasons, historical paid loss development methods are often slow to react to situations when new or different factors arise than those that have affected paid losses in the past.

•Historical incurred loss development methods: These methods, like historical paid loss development methods, assume that the ratio of losses in one period to losses in an earlier period will remain constant in the future. However, instead of using paid losses, these methods use incurred losses (i.e., the sum of cumulative historical loss payments plus outstanding case reserves) over discrete periods of time to estimate future losses. Historical incurred loss development methods can be preferable to historical paid loss development methods because they explicitly take into account open cases and the claims adjusters’ evaluations of the cost to settle all known claims. However, historical incurred loss development methods necessarily assume that case reserving practices are consistently applied over time. Therefore, when there have been significant changes in how case reserves are established, using incurred loss data to project ultimate losses can be less reliable than other methods.

•Expected loss ratio methods: These methods are based on the assumption that ultimate losses vary proportionately with premiums. Expected loss ratios are typically developed based upon the information used in pricing and are multiplied by the total amount of premiums earned to calculate ultimate losses. Expected loss ratio methods are useful for estimating ultimate losses in the early years of long-tail lines of business, when little or no paid or incurred loss information is available.

•Bornhuetter-Ferguson methods: These methods are a blend of the expected loss ratio and loss development methods. The percent of incurred (or paid) loss to ultimate loss implied by the selected development pattern from the incurred (or paid) loss development method is used to determine the percentage of ultimate loss yet to be developed. Inception to date losses are added to losses yet to be developed, yielding an estimate of ultimate for each year of account.

•Adjusted historical paid and incurred loss development methods: These methods take traditional historical paid and incurred loss development methods and adjust them for the estimated impact of changes from the past in factors such as inflation, the speed of claims payment or the adequacy of case reserves. Adjusted historical paid and incurred loss development methods are often more reliable methods of predicting ultimate losses in periods of significant change, provided the actuaries can develop methods to reasonably quantify the impact of changes.

As part of Ark’s quarterly actuarial review, Ark compares the previous quarter’s projections of incurred, paid and case reserve activity, including amounts incurred but not reported, to actual amounts experienced in the quarter. Differences between previous estimates and actual experience are evaluated to determine whether a given actuarial method for estimating loss and LAE reserves should be relied upon to a greater or lesser extent than it has been in the past. While some variance is expected each quarter due to the inherent uncertainty in estimating loss and LAE reserves, persistent or large variances would indicate that prior assumptions and/or reliance on certain actuarial methods may need to be revised going forward.

Upon completion of each quarterly review, Ark selects indicated loss and LAE reserve levels based on the results of the actuarial methods described previously, which are the primary consideration in determining management's best estimate of required loss and LAE reserves. However, in making its best estimate, management also considers other qualitative factors that may lead to a difference between held reserves and the actuarial central estimate of reserves. Typically, these qualitative factors are considered when management and Ark’s actuaries conclude that there is insufficient historical incurred and paid loss information or that trends included in the historical incurred and paid loss information are not likely to repeat in the future. Such qualitative factors include, among others, recent entry into new markets or new products, improvements in the claims department that are expected to lessen future ultimate loss costs, legal and regulatory developments or other uncertainties that may arise.

The process of establishing loss and LAE reserves, including amounts incurred but not reported, is complex and imprecise, as it must consider many variables that are subject to the outcome of future events. As a result, informed subjective estimates and judgments as to the ultimate exposure to losses are an integral component of the loss and LAE reserving process. Ark categorizes and tracks insurance and reinsurance reserves by “reserving class of business” for each underwriting office, London and Bermuda, and then aggregates the reserving classes by line of business, which are summarized herein as property and accident & health, specialty, marine & energy, casualty-active and casualty-runoff.

The major causes of material uncertainty (i.e., reserving factors) generally will vary for each line of business, as well as for each separately analyzed reserving class of business within the line of business. Also, reserving factors can have offsetting or compounding effects on estimated loss and LAE reserves. In most cases, it is not possible to measure the effect of a single reserving factor and construct a meaningful sensitivity expectation. Actual results will likely vary from expectations for each of these assumptions, resulting in an ultimate claims liability that is different from that being estimated currently.

Additional causes of material uncertainty exist in most product lines and may impact the types of claims that could occur within a particular line of business or reserving class of business. Examples where reserving factors, within a line of business or reserving class of business, are subject to change include changing types of insureds (e.g., size of account, industry insured, jurisdiction), changing underwriting standards, or changing policy provisions (e.g., deductibles, policy limits, endorsements).

For property reserving classes, the reserve risk is driven primarily by occasional catastrophe events, though the financial effect of these is mitigated by reinsurance and retrocessional purchases. Ark writes property business on both an insurance and reinsurance basis. The insurance business primarily consists of direct and facultative contracts. However, some business is written through line slips and MGA binding authorities, which could have a longer-tail due to the increased exposure period caused by underlying policies attaching to the binder contract. The reinsurance business can also have a longer-tail due to timing delays resulting from attachment points on excess of loss contracts.

For accident & health reserving classes, the losses emanate from a wide range of personal accident, sickness, travel and medical insurance risks. The underlying business is a mix of direct and facultative contracts, as well as some MGA and reinsurance contracts, which are typically shorter-tail lines. Certain smaller components of the accident & health business can be longer-tail. The accident & health business is also exposed to occasional catastrophic events though not to the same degree as the property business.

The marine reserving classes consist primarily of marine hull, cargo and specie risks. These all generally have some element of transportability, which mitigates the catastrophe risk exposure; for example, having the ability to move out of the path of a hurricane if provided with sufficient notice. The marine reserving classes are generally shorter-tail.

The energy platform reserving classes cover risks that are less transportable and therefore are exposed to catastrophe events similar to property reserving classes. Other energy reserving classes cover construction contracts, which often have considerably protracted exposure periods with the bulk of the risk towards the end of the coverage period. This can have the effect of increasing the tail on an otherwise short-tail reserving class.

Ark’s specialty portfolio is comprised of a diverse portfolio of insurance and reinsurance subclasses of business including aviation, space, political and credit, cyber, terrorism and political violence, nuclear, fine art & specie, surety and mortgage. Certain subclasses of business are exposed to both catastrophe events and man-made loss events; for example, terrorism, war and war-like actions, political violence and space. Although these subclasses have different coverages and exposures, they are all short-tail in nature and have similar reserving features.

The casualty–active line of business consists of U.S. reinsurance and insurance risks written on an excess of loss basis. The casualty–runoff line of business consists of international reinsurance risks and U.S. casualty insurance risks written through an MGA binding authority. The losses arising from these lines of business are primarily related to medical malpractice, professional liability and general liability coverages, which are long-tail lines of business.

Casualty policies are generally written on either a claims-made or occurrence basis. On a claims-made basis, the trigger of loss is based on the date that the loss is reported. On an occurrence basis, the trigger of loss is the date that the loss occurred. Due to delays between loss occurrence and loss reporting, business written on an occurrence basis can be longer-tail than business written on a claims-made basis.

For the years of account prior to the Ark Transaction, a significant proportion of the Syndicates’ underwriting capital was provided by TPC Providers using whole account reinsurance contracts with Ark’s corporate member. For the years of account subsequent to the Ark Transaction, Ark is no longer using TPC Providers to provide underwriting capital for the Syndicates.

A Reinsurance to Close (“RITC”) agreement is generally put in place after the third year of operations for a year of account such that the outstanding loss and LAE reserves, including future development thereon, are reinsured into the next year of account. As a result, and in combination with the changing participation provided by TPC Providers, Ark’s participation on outstanding loss and LAE reserves reinsured into the next year of account changes. After 2023, Ark is no longer subject to changes in TPC Providers’ participation.

During 2023, an RITC agreement was executed such that the outstanding loss and LAE reserves for claims arising out of the 2020 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 42.8%, were reinsured into the 2021 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 0.0%.

During 2022, an RITC agreement was executed such that the outstanding loss and LAE reserves for claims arising out of the 2019 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 58.3%, were reinsured into the 2020 year of account, for which the TPC Providers’ participation in the total net results of the Syndicates was 42.8%.


	Year Ended December 31,
Millions	2024		2023		2022
Gross beginning balance	$	1,605.1	$	1,296.5	$	894.7
Less: beginning reinsurance recoverable on unpaid losses (1)	(340.8)		(505.0)		(428.9)
Net loss and LAE reserves	1,264.3		791.5		465.8

Loss and LAE incurred relating to:
Current year losses	914.4		706.9		588.1
Prior year losses	(58.6)		19.9		(51.7)
Net incurred loss and LAE	855.8		726.8		536.4

Loss and LAE paid relating to:
Current year losses	(109.2)		(51.3)		(98.9)
Prior year losses	(307.5)		(356.6)		(158.6)
Net paid loss and LAE	(416.7)		(407.9)		(257.5)

Change in TPC Providers’ participation (2)	—		145.4		57.5
Foreign currency translation and other adjustments to loss and LAE reserves	(10.3)		8.5		(10.7)

Net ending balance	1,693.1		1,264.3		791.5
Plus: ending reinsurance recoverable on unpaid losses (3)	434.4		340.8		505.0
Gross ending balance	$	2,127.5	$	1,605.1	$	1,296.5

During the year ended December 31, 2024, the Ark/WM Outrigger segment experienced $58.6 million of net favorable prior year loss reserve development. The net favorable prior year loss reserve development was driven primarily by the specialty ($34.3 million) and property and accident & health ($29.2 million) reserving lines of business, partially offset by net unfavorable development in the casualty-active ($4.5 million) reserving line of business. The net favorable prior year loss reserve development was driven primarily by positive claims experience in specialty for the 2023 and 2019 accident years and in property and accident & health for the 2023 accident year.

During the year ended December 31, 2023, the Ark/WM Outrigger segment experienced $19.9 million of net unfavorable prior year loss reserve development. The net unfavorable prior year loss reserve development was driven primarily by the property and accident & health ($41.7 million) reserving line of business, partially offset by net favorable prior year loss reserve development within the specialty ($11.9 million) and casualty–runoff ($6.0 million) reserving lines of business. The net unfavorable prior year loss reserve development in the property and accident & health reserving line of business was driven primarily by Hurricane Ian and Winter Storm Elliott within the 2022 accident year. The net favorable prior year loss reserve development in specialty and casualty-runoff was driven primarily by positive claims experience for the 2021 and 2020 accident years.

During the year ended December 31, 2022, The Ark/WM Outrigger segment experienced $51.7 million of net favorable prior year loss reserve development. The net favorable prior year loss reserve development was driven primarily by the property and accident & health ($20.8 million), marine & energy ($18.8 million) and specialty ($12.7 million) reserving lines of business. The net favorable prior year loss reserve development in property and accident & health, marine & energy and specialty was driven primarily by positive claims experience for the 2021 accident year.


	Year Ended December 31,
Millions	2024		2023
Property and Accident & Health (1)	$	533.6	$	358.7
Marine & Energy	463.1		331.7
Specialty	417.0		339.7
Casualty-Active	178.0		137.1
Casualty-Runoff	66.5		81.3
WM Outrigger Re	34.9		15.8
Unpaid loss and LAE reserves, net of reinsurance recoverables on unpaid losses (1)	1,693.1		1,264.3
Plus: Reinsurance recoverables on unpaid losses
Property and Accident & Health (2)	121.5		126.9
Marine & Energy	180.1		59.1
Specialty	51.3		77.6
Casualty-Active	80.7		74.8
Casualty-Runoff	.8		2.4
Total Reinsurance recoverables on unpaid losses (2)	434.4		340.8
Total unpaid loss and LAE reserves	$	2,127.5	$	1,605.1

The following five tables cover each of Ark’s property and accident & health, marine & energy, specialty, casualty-active and casualty-runoff reserving lines of business and are presented net of reinsurance, which includes the impact of whole-account quota-share reinsurance arrangements related to TPC Providers. Each of the five tables includes three sections as follows:

The top section of the table presents, for each of the previous 10 accident years: (1) cumulative total undiscounted incurred loss and LAE as of each of the previous 10 year-end evaluations, (2) total IBNR plus expected development on reported claims as of December 31, 2024 and (3) the cumulative number of reported claims as of December 31, 2024.

The middle section of the table presents cumulative paid loss and LAE for each of the previous 10 accident years as of each of the previous 10 year-end evaluations. Also included in this section is a calculation of the loss and LAE reserves as of December 31, 2024, which is then included in the reconciliation to the consolidated balance sheet presented above. The total unpaid loss and LAE reserves as of December 31, 2024 are calculated as the cumulative incurred loss and LAE from the top section less the cumulative paid loss and LAE from the middle section, plus any outstanding liabilities from accident years prior to 2014.

The bottom section of the table is supplementary information about the average historical claims duration as of December 31, 2024. It shows the weighted average annual percentage payout of incurred loss and LAE by accident year as of each age. For example, the first column is calculated as the incremental paid loss and LAE in the first calendar year for each given accident year (e.g. calendar year 2024 for accident year 2024, calendar year 2023 for accident year 2023) divided by the cumulative incurred loss and LAE as of December 31, 2024 for that accident year. The resulting ratios are weighted using cumulative incurred loss and LAE as of December 31, 2024.


Property and Accident & Health
$ in Millions
	Incurred Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,																				As of December 31, 2024
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024		Total IBNR plus expected development on reported claims		Cumulative number of reported claims
	Unaudited
2015	$	19.1	$	18.1	$	17.2	$	16.2	$	16.0	$	16.0	$	15.8	$	15.7	$	16.0	$	16.1	$	.1	2,829
2016			22.2		17.5		18.2		18.4		18.3		18.5		18.5		18.5		18.5		.2		3,433
2017					31.1		37.7		$	45.2	44.2		42.8		42.3		43.8		43.4		15.8		4,624
2018							40.7		$	47.1	49.0		46.7		46.8		46.3		46.4		1.9		4,288
2019									33.9		31.2		27.0		23.8		23.2		22.8		.6		4,024
2020											76.9		75.1		74.5		77.6		79.5		9.9		4,646
2021													170.0		153.7		165.3		168.0		7.5		3,509
2022															241.5		266.9		277.3		12.9		4,044
2023																	213.9		176.1		77.3		3,598
2024																			359.5		202.7		3,614
																	Total		$	1,207.6


Property and Accident & Health
Millions
	Cumulative Paid Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024
	Unaudited
2015	$	6.9	$	12.2	$	13.4	$	14.6	$	14.5	$	14.8	$	15.0	$	15.0	$	15.4	$	15.6
2016			8.5		13.0		16.3		16.7		16.8		17.1		17.7		17.9		18.1
2017					16.8		25.7		31.5		32.7		29.4		27.1		25.4		28.2
2018							15.6		32.2		40.1		40.0		40.8		42.8		43.6
2019									6.8		16.7		18.3		18.5		19.3		20.6
2020											11.2		33.9		46.9		55.6		66.5
2021													30.7		86.5		129.8		142.7
2022															69.4		191.9		229.4
2023																	19.9		52.9
2024																			54.8
																	Total		672.4
All outstanding liabilities before 2015, net of reinsurance																			1.5
Loss and LAE reserves, net of reinsurance																			$	536.7


Marine & Energy
$ in Millions
	Incurred Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,																				As of December 31, 2024
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024		Total IBNR plus expected development on reported claims		Cumulative number of reported claims
	Unaudited
2015	$	21.7	$	17.4	$	16.1	$	13.3	$	12.7	$	12.8	$	12.7	$	12.9	$	12.7	$	12.7	$	—	3,243
2016			23.4		19.5		15.6		14.6		14.3		14.8		14.1		13.6		13.3		—		3,772
2017					26.0		19.3		17.6		16.9		16.6		15.8		16.0		16.1		.4		4,139
2018							25.4		19.9		17.4		17.8		17.3		17.7		16.7		.2		3,238
2019									23.7		21.6		21.6		21.4		21.9		21.2		.5		2,393
2020											29.7		27.1		28.5		27.4		27.1		.8		1,582
2021													86.2		69.3		67.3		74.5		4.0		1,505
2022															149.7		153.6		156.0		31.9		1,968
2023																	197.0		188.2		115.9		2,138
2024																			239.9		182.6		1,485
																	Total		$	765.7


Marine & Energy
Millions
	Cumulative Paid Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024
	Unaudited
2015	$	4.0	$	7.8	$	9.6	$	11.0	$	10.4	$	10.5	$	10.9	$	11.5	$	11.6	$	11.6
2016			5.5		10.0		12.6		13.0		13.1		13.7		13.4		13.4		13.4
2017					5.1		11.1		12.8		14.0		14.1		14.1		14.0		14.3
2018							2.6		12.4		13.9		14.6		15.3		15.3		15.4
2019									3.3		10.6		12.6		14.3		15.3		18.1
2020											3.1		12.7		16.0		18.5		21.9
2021													6.3		24.3		38.2		51.9
2022															12.2		66.2		97.7
2023																	10.5		42.1
2024																			20.9
																	Total		307.3
All outstanding liabilities before 2015, net of reinsurance																			4.7
Loss and LAE reserves, net of reinsurance																			$	463.1


Specialty
$ in Millions
	Incurred Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,																				As of December 31, 2024
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024		Total IBNR plus expected development on reported claims		Cumulative number of reported claims
	Unaudited
2015	$	17.3	$	14.6	$	12.3	$	10.7	$	11.0	$	11.2	$	11.1	$	8.9	$	8.1	$	11.3	$	.3	1,841
2016			18.2		14.3		10.9		11.3		11.8		11.8		8.9		8.5		12.3		.4		1,936
2017					17.9		12.8		11.9		11.4		11.6		10.6		10.3		10.9		.4		2,195
2018							14.4		16.2		16.6		15.9		14.8		15.7		16.6		.4		2,122
2019									21.6		19.4		18.6		25.6		30.1		19.9		.3		2,387
2020											23.7		22.8		18.6		19.5		16.7		.9		2,017
2021													70.3		62.1		51.4		43.8		10.0		1,725
2022															180.3		174.8		168.4		77.0		1,496
2023																	214.5		197.4		94.4		1,641
2024																			218.7		141.6		1,292
																	Total		$	716.0


Specialty
Millions
	Cumulative Paid Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024
	Unaudited
2015	$	4.0	$	7.0	$	7.6	$	8.0	$	8.0	$	8.1	$	8.1	$	6.4	$	6.2	$	9.3
2016			3.2		7.9		9.1		9.9		10.3		10.3		8.5		8.3		11.7
2017					3.1		6.5		8.3		8.5		8.5		9.2		8.9		9.6
2018							2.7		8.2		9.9		10.4		11.8		13.0		14.1
2019									4.8		6.9		7.4		18.2		25.1		17.6
2020											5.0		10.5		12.9		17.7		17.7
2021													5.0		23.9		35.5		34.6
2022															16.0		61.7		82.5
2023																	18.4		75.2
2024																			27.3
																	Total		299.6
All outstanding liabilities before 2015, net of reinsurance																			.6
Loss and LAE reserves, net of reinsurance																			$	417.0


Casualty-Active
$ in Millions
	Incurred Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,																				As of December 31, 2024
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024		Total IBNR plus expected development on reported claims		Cumulative number of reported claims
	Unaudited
2015	$	9.6	$	9.7	$	8.2	$	8.1	$	7.4	$	7.1	$	7.0	$	7.3	$	7.5	$	7.4	$	.5	1,306
2016			8.8		8.3		8.9		9.0		9.1		9.2		9.2		10.1		11.8		.5		1,588
2017					11.5		11.7		10.8		9.3		9.0		10.5		10.6		10.9		.8		1,667
2018							12.9		13.3		11.1		10.8		8.6		9.1		9.4		1.1		1,147
2019									14.8		13.7		12.3		10.6		11.4		13.0		1.7		1,019
2020											13.5		12.0		10.8		9.2		8.8		2.0		665
2021													21.4		22.4		16.6		16.3		6.4		961
2022															32.9		38.0		34.6		27.9		1,558
2023																	60.9		65.9		57.4		1,792
2024																			59.5		54.9		1,170
																	Total		$	237.6


Casualty-Active
Millions
	Cumulative Paid Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024
	Unaudited
2015	$	1.8	$	2.4	$	3.2	$	4.4	$	4.7	$	4.9	$	5.1	$	5.5	$	6.1	$	6.3
2016			.2		1.0		2.3		4.0		4.6		5.3		6.5		8.1		9.7
2017					.8		1.7		2.7		3.4		4.2		5.7		7.5		8.3
2018							.3		1.4		3.5		4.3		4.3		6.2		7.1
2019									.3		1.4		2.3		3.0		5.7		8.3
2020											.5		1.0		2.0		3.3		5.3
2021													.5		.9		3.1		9.6
2022															.4		1.5		2.4
2023																	.9		5.6
2024																			1.9
																	Total		64.5
All outstanding liabilities before 2015, net of reinsurance																			4.9
Loss and LAE reserves, net of reinsurance																			$	178.0


Casualty-Runoff
$ in Millions
	Incurred Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,																				As of December 31, 2024
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024		Total IBNR plus expected development on reported claims		Cumulative number of reported claims
	Unaudited
2015	$	36.4	$	31.9	$	33.1	$	36.6	$	36.3	$	37.3	$	36.7	$	39.1	$	40.2	$	39.4	$	1.9	1,950
2016			32.4		32.1		40.3		38.4		38.7		38.4		37.6		37.3		37.4		2.0		2,150
2017					30.5		33.8		31.3		32.0		31.5		29.8		28.2		28.4		2.3		1,604
2018							33.5		28.1		27.2		26.5		26.1		27.9		27.7		3.4		1,280
2019									26.4		23.2		23.3		24.8		23.5		23.6		5.2		973
2020											15.8		12.2		13.8		10.9		9.5		2.9		567
2021													10.4		7.0		5.4		4.5		1.8		283
2022															.8		2.6		2.5		1.6		80
2023																	2.7		3.6		2.4		40
2024																			1.3		.7		22
																	Total		$	177.9


Casualty-Runoff
Millions
	Cumulative Paid Loss and LAE, Net of Reinsurance
	For the Years Ended December 31,
Accident Year	2015		2016		2017		2018		2019		2020		2021		2022		2023		2024
	Unaudited
2015	$	4.3	$	8.2	$	14.5	$	21.4	$	24.6	$	27.3	$	28.9	$	33.0	$	35.3	$	35.8
2016			3.9		10.1		17.7		22.7		25.3		27.8		28.7		30.9		32.4
2017					3.2		9.4		14.6		18.4		21.3		22.5		22.8		23.5
2018							3.4		7.4		12.6		14.9		16.2		18.2		21.3
2019									3.3		5.8		7.8		12.1		15.1		15.8
2020											.8		1.3		3.1		6.0		6.3
2021													.5		1.7		1.8		2.3
2022															.3		.5		.7
2023																	.9		1.0
2024																			.5
																	Total		139.6
All outstanding liabilities before 2015, net of reinsurance																			28.2
Loss and LAE reserves, net of reinsurance																			$	66.5

As of December 31, 2024 and 2023, HG Re did not have any outstanding loss and LAE reserves. For the years ended December 31, 2024, 2023 and 2022, HG Re did not recognize any incurred loss and LAE. For the year ended December 31, 2024, HG Re recognized gross incurred loss and LAE of $0.3 million related to a delinquent payment by a reinsured BAM policyholder. Net of recoveries, HG Re recognized no incurred loss and LAE.

White Mountains’s insurance operations are subject to regulation and supervision in each of the jurisdictions where they are domiciled and licensed to conduct business. Generally, regulatory authorities have broad supervisory and administrative powers over such matters as licenses, standards of solvency, premium rates, policy forms, investments, security deposits, methods of accounting, form and content of financial statements, minimum capital and surplus requirements, dividends and other distributions to shareholders, periodic examinations and annual and other report filings. In general, such regulation is for the protection of policyholders rather than shareholders.

The Insurance Act 1978 of Bermuda and related regulations, as amended (the “Insurance Act”), regulates the insurance business of Bermuda-domiciled insurers. Under the Insurance Act, insurers are required to maintain available statutory capital and surplus at a level equal to or in excess of its enhanced capital requirement which is established by reference to either a Bermuda Solvency Capital Requirement (“BSCR”) model or an approved internal capital model. Generally, the BMA has broad supervisory and administrative powers over such matters as licenses, standards of solvency, investments, methods of accounting, form and content of financial statements, minimum capital and surplus requirements and annual and other report filings.

The Syndicates are subject to oversight by the Council of Lloyd’s. Ark Syndicate Management Limited is authorized by the U.K.’s Prudential Regulation Authority (the “PRA”) and regulated by the Financial Conduct Authority under the Financial Services and Markets Act 2000. The underwriting capacity of a Member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit in an amount determined under the capital adequacy regime of the PRA. This amount is determined by Lloyd’s and is based on each syndicate’s solvency and capital requirement as calculated through its internal model. In addition, if the Funds at Lloyd’s are not sufficient to cover all losses, the Lloyd’s Central Fund provides an additional discretionary level of security for policyholders. As of December 31, 2024, Ark had provided Funds at Lloyd’s of $361.5 million.

WM Outrigger Re is a special purpose insurer under Bermuda insurance regulations and is subject to regulation and supervision by the BMA. As of December 31, 2024, WM Outrigger Re had statutory capital and surplus of $196.3 million. As a special purpose insurer, Outrigger Re Ltd. has a nominal minimum regulatory capital requirement of $1.

Bamboo Captive is a protected cell captive domiciled in the state of Arizona and is subject to regulation and supervision by the Arizona Department of Insurance and Financial Institutions (“Arizona DIFI”). As an Arizona-domiciled protected cell, Bamboo Captive is required to maintain $0.5 million of minimum capital. As of December 31, 2024, Bamboo Captive had statutory capital and surplus of $6.8 million.

There are no restrictions under Bermuda law or the law of any other jurisdiction on the payment of dividends from retained earnings by White Mountains, provided that after the payment of any dividend, the Company would continue to be able to pay its liabilities as they become due and the realizable value of the Company’s assets would remain greater that its liabilities. Following is a description of the dividend capacity of White Mountains’s insurance and reinsurance subsidiaries:

During any 12-month period, GAIL, a class 4 licensed Bermuda insurer, has the ability to (i) make capital distributions of up to 15% of its total statutory capital per the previous year’s statutory financial statements or (ii) make dividend payments of up to 25% of its total statutory capital and surplus per the previous year’s statutory financial statements, without prior approval of Bermuda regulatory authorities. Accordingly, GAIL will have the ability to pay a dividend of up to $336.7 million during 2025, which is equal to 25% of its statutory capital and surplus of $1,346.7 million as of December 31, 2024, subject to meeting all appropriate liquidity and solvency requirements and the filing of its December 31, 2024 statutory financial statements. During 2024, GAIL did not pay any dividends to its immediate parent.

HG Re is a special purpose insurer subject to regulation and supervision by the BMA. HG Re does not require regulatory approval to pay dividends; however, its dividend capacity is limited to amounts held outside of the Collateral Trusts pursuant to the FLRT with BAM. As of December 31, 2024, HG Re had $6.5 million of net unrestricted cash. As of December 31, 2024, HG Re had $157.5 million of accrued interest on the BAM Surplus Notes held outside the Collateral Trusts. As of December 31, 2024, HG Re had $718.3 million of statutory capital and surplus and $950.1 million of assets held in the Collateral Trusts.