Atrium results and updated forecasts - 2021 account remains open as at 31 December 2025

Atrium Underwriters Limited has provided us with an update on the open years and the overall performance of Syndicate 609 as at 31 December 2025.

The calendar year result for the syndicate in 2025 is a profit of £122m (up from £58.8m in 2024) at a combined ratio of 90.4% (99.5% in 2024).

The 2023 year of account has closed with a profit of £130m or 14.94% of allocated capacity. The forecast as at 30 September 2025 was a profit in the range 12.5% to 17.5% of capacity. Capacity in 2023 was £870m.

The 2024 year is forecast to make a profit, with the range of forecast results unchanged at between 5% and 15% of capacity. 2024 capacity was £921m.

The 2021 year of account was not closed by reinsurance as at 31 December 2024 and will remain open as at 31 December 2025. The underwriting year is exposed to the fate of western owned aircraft, leased to operators in Russia at the time of invasion of Ukraine in February 2022. The position regarding claims for these stranded aircraft is complicated and continues to develop.

The managing agent adopted a probabilistic approach to deriving reserves for the events. This considers the financial implications of many different potential outcomes. This approach has continued with assumptions updated at the end of 2025 for potential costs and likelihood of the modelled outcomes. These have also been updated following some settlements with policyholders as well as the judgement handed down by the High Court of England and Wales in June 2025. The changes to the assumptions has resulted in an increase in the estimated ultimate loss assessment for the syndicate. The gross loss estimate has increased to £513m (from £393m at year ended 31 December 2024) with an estimate loss cost after reinsurance recoveries of £146m (previously 114m).

The cumulative loss on the year to date has improved by £2.1m in the calendar year and now stands at £20.2m (a loss of 3.2% on a capacity of £625m). Given the underlying circumstances, both in terms of the original claims and also in relation to the associated reinsurance recoveries, there continues to be more than the normal level of reserve sensitivity and the managing agent believes that the final result could be in a much wider range than would be usual at this stage of its development. The account will continue to remain open until the range of reserve sensitivity normalises. Atrium has provided a range of outcomes between a best case profit of 5% of capacity and worse case loss of 5%. This range is unchanged from that published as at 30 September 2025.

The syndicate report and account has been published to the Atrium website is and is available here.