Lloyd's of London reported a 2017 pretax loss of £2 billion ($2.80 billion), it said on Wednesday, pushing it into the red for the first time in six years after a record year for losses from natural disasters.
The specialist insurance market, which has been losing global market share, also said its planned EU subsidiary would be operational by July 2018, to cope with Britain's departure from the European Union.
Insurers suffered $135 billion in losses from natural catastrophes such as hurricanes, earthquakes and wildfires last year.
The £2 billion loss followed a pretax profit of £2.1 billion in 2016.
"The market experienced an exceptionally difficult year in 2017, driven by challenging market conditions and a significant impact from natural catastrophes," chief executive Inga Beale said in a trading statement.