Rate increases in excess casualty may be close to their peak, according to WTW's latest outlook for the North American insurance market.
However, auto liability and some of the most difficult general liability classes remain the main exceptions to a market that it said is largely favorable for buyers.
In its fall Insurance Marketplace Realities report, the broker attributed the possible turn in excess casualty to new capacity from MGAs and broker-led facilities, years of cumulative rate increases, and insurers deploying smaller limits.
Property is where buyers are seeing the biggest changes. WTW forecasts reductions of 5% to 15% for single-carrier programs and 15% to 25% for shared and layered programs.
Across its own large and complex portfolio, the broker said average renewal rates fell 14.5% in the second quarter of 2026, compared with 8.4% a year earlier. Shared and layered programs with five or more carriers averaged reductions of 23.41%. WTW said rates appear to be heading back toward 2019 levels, and that the trend should continue through year-end unless a catastrophe of $150 billion or more occurs.
Insured catastrophe losses in the first half of 2026 totaled $42 billion, the lowest first half since 2020. Insurers are increasingly willing to improve terms, deductibles and wordings as competition increases.
There is one cost pressure buyers can't negotiate away. WTW said replacement cost inflation is accelerating again in 2026, driven by US tariffs and pressure on energy and supply chains, which makes up-to-date property valuations more important.
Casualty rates are still rising, though more slowly. WTW's casualty forecast puts general liability at 2% to 10%. Auto liability is expected to rise 8% to 15% for low and moderate hazard risks, and 10% to 20% for high-hazard or challenged classes. Umbrella and excess liability for challenged classes face increases of 8% to 15%.
Workers' compensation is the only casualty line consistently seeing rate reductions, with a forecast range of minus 3% to plus 2%.
WTW said the underlying loss trends haven't changed even as pricing stabilizes. Social inflation, nuclear verdicts, third-party litigation funding and adverse development continue to drive disciplined underwriting. Many buyers have responded by retaining more risk through higher deductibles, self-insured retentions and captives.
The report's theme for this year is specialist expertise in a changing risk landscape. WTW said it references AI more than 70 times and data centers more than 20 times. The rapid growth of AI, cloud computing and digital infrastructure is creating demand for specialist cover, and emerging exposures cut across traditional lines of business.
The broker also said geopolitical volatility continues to affect political violence, terrorism and marine, but capacity in those lines remains resilient.
For retail brokers, the outlook confirms a split market heading into January 1 renewals. Property buyers have real leverage, especially on layered programs where carriers are competing for share. Brokers who bring accurate, recently updated valuations to market are best placed to secure rate reductions and improved terms, without exposing clients to underinsurance as rebuilding costs rise.
On the casualty side, the possible peak in excess pricing is the most important signal. It is still only a possibility, though. Clients with fleets or challenged general liability classes face another year of double-digit increases. For them, reviewing retentions and program structure may do more to control costs than marketing the account.
