London's treaty reinsurance market posted its first premium decline in years in 2025. The fall came even as the business line's share of the London company market held broadly steady.
New data from the International Underwriting Association (IUA) shows total treaty premiums written in London fell 6% to £11.27 billion in 2025. The figures were released at the Rendez-Vous de Septembre in Monte Carlo. That compares with £11.985 billion in 2024. Treaty business now accounts for 26% of total London company market premiums, broadly unchanged from 27% the previous year.
The 2025 total still represents more than double the £5.32 billion written in 2020. Six years ago, treaty business made up just 19% of the London company market. The fall from the 2024 peak reflects a deliberate response to pricing conditions rather than a structural retreat.
"The figures from the latest London company market premium statistics survey clearly illustrate a shift to a more competitive pricing environment, compared to the hard market cycle observed in recent years," said Scott Farley, director of communications at IUA. The IUA characterises the fall as a deliberate response to pricing conditions rather than a structural retreat.
The IUA data offers some granularity on where that selectivity played out. Property remained the largest treaty class at £3.083 billion, followed by motor at £2.393 billion, marine at £1.555 billion, and liability at £1.365 billion.
The UK and Ireland account for more than half of the treaty premium base at £6.328 billion. The US and Canada is the most important international source at £2.517 billion, with continental Europe at £1.437 billion.
Controlled business tells a different story. Treaty reinsurance written through overseas or UK regional offices, but managed from London, rose nearly 10% to £621 million in 2025. That compares with £567 million in 2024. That divergence points to London operations expanding international reach even as the core book contracted.
The 6% decline arrives at a moment of wider market transition. PwC modelled the London market entering the current softening phase from a materially stronger base than during the previous soft cycle. The analysis was published ahead of this year's Rendez-Vous. Pricing headroom remains, PwC found, though it will narrow as competition intensifies. S&P Global Ratings flagged that softening is expected to continue into 2027, with traditional reinsurance capacity the primary driver of price competition.
For reinsurance buyers and the brokers who place their programmes, a softer London market means greater negotiating room on price and terms. The discipline exercised by IUA members, signalled in Farley's framing of growth as selective, is the constraint that keeps that room from becoming disorderly. Whether it holds through the January 2027 renewal cycle is the more consequential question.
