The business of legacy insurance – once a niche exercise in tidying up old books of business – is now a trillion-dollar enterprise. According to PwC’s Global Insurance Run-Off Survey 2025, global non-life reserves in run-off stand at $1.129 trillion, up 11 percent since the last survey.
For U.S. carriers, the market’s growth reflects a familiar set of pressures: adverse casualty experience, rising social inflation, and capital strain from long-tail liabilities. As PwC noted, “casualty reserves have been strengthened across the market on account of adverse experience, especially from the 2013-2019 soft market underwriting years.” Insurers who once hoped those years would fade quietly into the background are instead finding that claims are arriving later, costlier, and more volatile than expected.
Run-off activity in North America has become more than a clearing house for legacy asbestos. In 2024, 33 transactions were publicly announced worldwide, transferring $6.6 billion of liabilities. A further 25 deals were struck in the first eight months of 2025, many falling in the $250 million to $1 billion band.
Connie Tregidga, Group M&A Director at Compre Group, described the shift in approach: “Creating bespoke solutions that go beyond solving for the immediate capital need is key for our clients. Transaction structures are increasingly including an element of renewal or future exit as we become the trusted capital partner with appetite for long tail reserve risk.”
For U.S. carriers, this trend highlights a willingness to trade away the uncertainty of long-tail portfolios in exchange for capital certainty, even if it comes at a cost.
The legacy business has always been shaped by the courts, and new exposures are taking center stage. PwC’s survey singles out PFAS chemicals and sports-related head injuries as the next frontier.
Robert Reville, Head of Casualty Market Development at Moody’s, put it bluntly: “The increased exposure to complex multi-defendant litigation has significantly extended the long tail of liability. In this environment, a robust legacy market is an increasingly vital resource for insurer risk management.”
The NFL has already paid roughly $1 billion to more than 4,500 former players in concussion-related settlements, a figure that signals what other leagues and insurers could yet face. In the case of PFAS, dubbed “forever chemicals,” litigation is mounting against manufacturers and their insurers, with potential ripple effects across liability lines.
Even this conservative corner of the industry is being reshaped by technology. More than 80 percent of survey respondents said they expect generative AI to have a “moderate to significant impact” on run-off operations, particularly in due diligence and post-deal integration. At the same time, 32 percent cited data privacy and security risks, and 21 percent pointed to the problem of AI hallucinations.
For American insurers, run-off is no longer an afterthought but a strategic option. As reinsurers consolidate, and as reserve uncertainty grows, the ability to carve out a troubled book or ring-fence an exposure is increasingly valuable. That is especially true under U.S. accounting rules, which magnify volatility in results when adverse development strikes.
The question for the American market is not whether run-off will expand, but how. With specialist acquirers showing discipline and capital strength, and with litigation risks multiplying, carriers may find themselves returning to legacy solutions as routinely as they once turned to reinsurance treaties.
As Andy Ward and Rebecca Wilkinson of PwC wrote in their foreword: “This edition seeks to provide not just an analysis of where we are, but a framework to consider how this evolving market continues its journey.”
For the U.S. industry, that journey looks less like a tidy wind-down and more like a permanent fixture – a sector for all seasons.
