Property and casualty insurance claim and claim adjustment expense reserves represent the estimated amounts necessary to resolve all outstanding claims, including incurred but not reported (IBNR) claims as of the reporting date. The Company's reserve projections are based primarily on detailed analysis of the facts in each case, the Company's experience with similar cases and various historical development patterns. Consideration is given to historical patterns such as claim reserving trends and settlement practices, loss payments, pending levels of unpaid claims and product mix, as well as court decisions and economic conditions, including inflation, and public attitudes. All of these factors can affect the estimation of claim and claim adjustment expense reserves.

Establishing claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves for catastrophic events that have occurred, is an estimation process. Many factors can ultimately affect the final settlement of a claim and, therefore, the necessary reserve. Changes in the law, results of litigation, medical costs, the cost of repair materials and labor rates can affect ultimate claim costs. In addition, time can be a critical part of reserving determinations since the longer the span between the incidence of a loss and the payment or settlement of the claim, the more variable the ultimate settlement amount can be. Accordingly, short-tail claims, such as property damage claims, tend to be more reasonably estimable than long-tail claims, such as workers' compensation, general liability and professional liability claims. Adjustments to prior year reserve estimates, if necessary, are reflected in the results of operations in the period that the need for such adjustments is determined. There can be no assurance that the Company's ultimate cost for insurance losses will not exceed current estimates.

Catastrophes are an inherent risk of the property and casualty insurance business and have contributed to material period-to-period fluctuations in our results of operations and/or equity. The Company reported catastrophe losses, net of reinsurance, of $125 million and $75 million for the three months ended March 31, 2021 and 2020. Net catastrophe losses for the three months ended March 31, 2021 were primarily driven by Winter Storms Uri and Viola. Net catastrophe losses for the three months ended March 31, 2020 included $13 million related to the COVID-19 pandemic, with the remaining $62 million related primarily to U.S. weather related events.


For the three months ended March 31, 2021
(In millions)	2021		2020
Reserves, beginning of year:
Gross	$	22,706	$	21,720
Ceded	4,005		3,835
Net reserves, beginning of year	18,701		17,885
Reduction of net reserves due to Excess Workers' Compensation Loss Portfolio Transfer	(632)		—
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year	1,474		1,355
Increase (decrease) in provision for insured events of prior years	(54)		(8)
Amortization of discount	50		51
Total net incurred (1)	1,470		1,398
Net payments attributable to:
Current year events	(85)		(72)
Prior year events	(1,067)		(1,218)
Total net payments	(1,152)		(1,290)
Foreign currency translation adjustment and other	(32)		(88)
Net reserves, end of period	18,355		17,905
Ceded reserves, end of period	4,701		3,967
Gross reserves, end of period	$	23,056	$	21,872

(1) Total net incurred above does not agree to Insurance claims and policyholders' benefits as reflected on the Condensed Consolidated Statements of Operations due to amounts related to retroactive reinsurance deferred gain accounting, the loss on the Excess Workers' Compensation Loss Portfolio Transfer, uncollectible reinsurance and benefit expenses related to future policy benefits, which are not reflected in the table above.

Changes in estimates of claim and claim adjustment expense reserves, net of reinsurance, for prior years are defined as net prior year loss reserve development (development). These changes can be favorable or unfavorable. The following table presents development recorded for the Specialty, Commercial, International and Corporate & Other segments.


Three months ended March 31
(In millions)	2021		2020
Pretax (favorable) unfavorable development:
Specialty	$	(15)	$	(11)
Commercial	—		(4)
International	—		—
Corporate & Other	—		—
Total pretax (favorable) unfavorable development	$	(15)	$	(15)


Three months ended March 31
(In millions)	2021		2020
Pretax (favorable) unfavorable development:
Medical Professional Liability	$	8	$	10
Other Professional Liability and Management Liability	—		3
Surety	(15)		(30)
Warranty	(8)		—
Other	—		6
Total pretax (favorable) unfavorable development	$	(15)	$	(11)


Three months ended March 31
(In millions)	2021		2020
Pretax (favorable) unfavorable development:
Commercial Auto	$	—	$	9
General Liability	—		—
Workers' Compensation	—		(13)
Property and Other	—		—
Total pretax (favorable) unfavorable development	$	—	$	(4)

In 2010, Continental Casualty Company (CCC) together with several of the Company’s insurance subsidiaries completed a transaction with National Indemnity Company (NICO), a subsidiary of Berkshire Hathaway Inc., under which substantially all of the Company’s legacy A&EP liabilities were ceded to NICO through a Loss Portfolio Transfer (LPT). At the effective date of the transaction, the Company ceded approximately $1.6 billion of net A&EP claim and allocated claim adjustment expense reserves to NICO under a retroactive reinsurance agreement with an aggregate limit of $4 billion. The $1.6 billion of claim and allocated claim adjustment expense reserves ceded to NICO was net of $1.2 billion of ceded claim and allocated claim adjustment expense reserves under existing third-party reinsurance contracts. The NICO LPT aggregate reinsurance limit also covers credit risk on the existing third-party reinsurance related to these liabilities. The Company paid NICO a reinsurance premium of $2 billion and transferred to NICO billed third-party reinsurance receivables related to A&EP claims with a net book value of $215 million, resulting in total consideration of $2.2 billion.

In years subsequent to the effective date of the LPT, the Company recognized adverse prior year development on its A&EP reserves resulting in additional amounts ceded under the LPT. As a result, the cumulative amounts ceded under the LPT have exceeded the $2.2 billion consideration paid, resulting in the NICO LPT moving into a gain position, requiring retroactive reinsurance accounting. Under retroactive reinsurance accounting, this gain is deferred and only recognized in earnings in proportion to actual paid recoveries under the LPT. Over the life of the contract, there is no economic impact as long as any additional losses incurred are within the limit of the LPT. In a period in which the Company recognizes a change in the estimate of A&EP reserves that increases or decreases the amounts ceded under the LPT, the proportion of actual paid recoveries to total ceded losses is affected and the change in the deferred gain is recognized in earnings as if the revised estimate of ceded losses was available at the effective date of the LPT. The effect of the deferred retroactive reinsurance benefit is recorded in Insurance claims and policyholders' benefits on the Condensed Consolidated Statements of Operations.

The impact of the LPT on the Condensed Consolidated Statements of Operations was the recognition of a retroactive reinsurance benefit of $10 million and $14 million for the three months ended March 31, 2021 and 2020. As of March 31, 2021 and December 31, 2020, the cumulative amounts ceded under the LPT were $3.3 billion. The unrecognized deferred retroactive reinsurance benefit was $388 million and $398 million as of March 31, 2021 and December 31, 2020 and is included within Other liabilities on the Condensed Consolidated Balance Sheets.

NICO established a collateral trust account as security for its obligations to the Company. The fair value of the collateral trust account was $4.6 billion and $4.2 billion as of March 31, 2021 and December 31, 2020. In addition, Berkshire Hathaway Inc. guaranteed the payment obligations of NICO up to the aggregate reinsurance limit as well as certain of NICO’s performance obligations under the trust agreement. NICO is responsible for claims handling and billing and collection from third-party reinsurers related to the majority of the Company’s A&EP claims.

On February 5, 2021, CCC completed a transaction with Cavello Bay Reinsurance Limited (Cavello), a subsidiary of Enstar Group Limited, under which certain legacy excess workers’ compensation (EWC) liabilities were ceded to Cavello. Under the terms of the transaction, based on reserves in place as of January 1, 2020, the Company ceded approximately $690 million of net EWC claim and allocated claim adjustment expense reserves to Cavello under an LPT with an aggregate limit of $1 billion. The Company paid Cavello a reinsurance premium of $697 million, less claims paid between January 1, 2020 and the closing date of the agreement of $64 million. After transaction costs, the Company recognized an after-tax loss of approximately $12 million in the Corporate & Other segment for the three months ended March 31, 2021 related to the EWC LPT.

Cavello established a collateral trust account as security for its obligations to the Company, which will be maintained at 105% of outstanding reserves. As of March 31, 2021, the remaining amount available under the $1 billion aggregate limit of the EWC LPT was $310 million on an incurred basis.

The majority of the Company’s outstanding voluntary reinsurance receivables are due from reinsurers with financial strength ratings of A- or higher. Receivables due from reinsurers with lower financial strength ratings are primarily due from captive reinsurers and are backed by collateral arrangements.