Liability Insurers Face Unexpected Reserve Headwinds in Recent Years

Adverse development in 2025 concentrated in post-COVID accident years signals that loss trends are outpacing pricing assumptions industry-wide, S&P reports.
By: | March 19, 2026
Topics: Claims | Liability | News
analyzing financial trends

The U.S. property and casualty insurance industry recorded $7.30 billion in adverse one-year development within the other liability (occurrence) business lines in 2025 — raising new questions about reserve adequacy, according to analysis by S&P Global Market Intelligence.

Historically, other liability (occurrence) loss development flows through older accident years as claims mature over decades, the report said. Instead, 2025 data reveals a striking concentration in recent years.

Nearly $3 billion of reserve strengthening occurred in just accident years 2022 and 2023, with 2022 alone accounting for $1.45 billion in adverse movement. The trend exposes a critical problem: the industry is revising upward the ultimate loss estimates for immature underwriting years — the window where litigation dynamics and settlement trends can still dramatically expand, S&P said.

The pattern represents a marked departure from historical experience. Approximately 43.3% of total adverse development is tied to the three most recent accident years, while only 14.1% sits in the older tail where reserves traditionally unwind. This distribution suggests that reserving deficiencies are not burning off with time but instead reflecting underestimated loss trends in underwriting periods the industry expected would perform better, according to the report.

“The heavy concentration in accident years 2022 and 2023 is the most alarming, as it suggests the post-COVID underwriting years that many expected to benefit from hard market pricing are still being revised upward,” the S&P analysis noted. This dynamic creates particular concern for the business line’s most sensitive layers — umbrella and excess liability coverage — where small assumption shifts about severity can translate into billions in reserve movements.

Widespread Industry Pressure and Uneven Impact

The adverse development is not isolated to a handful of companies but rather systemic across the industry, according to S&P. Liberty Mutual Holding Co. Inc. led carriers with $1.26 billion in adverse development in 2025, followed by Chubb with $741.5 million and Berkshire Hathaway with $673.5 million. The adverse reserve development affects both primary carriers and global reinsurers, indicating that rising loss costs are transmitting throughout the entire liability market rather than remaining concentrated, the report said.

While some carriers posted substantial adverse development, other carriers — including Swiss Re, SCOR, Allianz, and Markel Group — reported favorable development. The disparity reflects differences in prior reserving conservatism, business mix, attachment points, and exposure to challenging litigation venues and claim types, according to S&P.

The underlying cause of adverse reserve development points to legal and social inflation that is evolving faster than insurers anticipated, the report said. Litigation dynamics and settlement inflation continue to surprise even disciplined reserving practices, particularly in immature accident years where exposure continues to accumulate.

Reconciling True Losses With Financial Reporting

A critical insight emerges when comparing gross Schedule P results in insurers’ statutory statements against net income figures affected by adverse development covers (ADC), S&P said. While reinsurance arrangements like ADC cushion the blow to reported earnings, they do not change the ultimate loss estimates — which continue climbing and creating pressure on reserve adequacy.

CNA Financial Corp. exemplified this dynamic by reporting $185 million in net unfavorable prior-year reserve development for 2025 while simultaneously recognizing $112.1 million in income related to an ADC from National Indemnity, the report said. The offset demonstrates how reinsurance structures manage volatility in calendar-year results but mask the underlying reserve pressure.

For industry participants and investors, focusing on gross results has become essential to understanding whether the market is genuinely adapting to new loss trends or simply deferring recognition of losses through reinsurance arrangements. The data suggests the former — that loss trends remain stubbornly ahead of assumptions, particularly for underwriting years that supposedly benefited from hard market pricing, S&P said. &

The R&I Editorial Team can be reached at [email protected].

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