Lloyd's of London has announced a 16 per cent dip in profit for the first half of 2017, and the group said it has not yet taken stock of the effects of recent devastating hurricanes in the Caribbean and United States.
However, chief executive Inga Beale told Reuters that net losses from the storms could reach $4.5bn (£3.4bn).
"There was limited major claim activity in the first half. There’s a very different second half emerging - it’s not only the hurricanes but we’ve got the Mexican earthquakes, floods in Asia, typhoons in Asia," she said.
"The hurricane season is still in play, earthquakes can happen at any time."
The insurance market reported pre-tax profit of £1.22bn, compared with £1.46bn this time last year.
Gross written premiums increased to £18.9bn, and the combined ratio improved to 96.9 per cent, from 98 per cent.
"These results highlight the continued strength of the Lloyd's market, but they do reflect the challenging conditions that have shaped the sector over recent years," said Beale.
"Our focus on maintaining a strong underwriting discipline and concentrating on profitable lines of business is showing signs of success, but we cannot allow that focus to waver if we are to continue to ensure the Lloyd's platform is the most attractive option for customers.
"Whilst these results do not cover the current hurricane season in the Caribbean and United States, the market is assessing claims and starting to make payments that will help local communities and businesses get back on their feet as quickly as possible. It is our ability to respond quickly and effectively in times like these that differentiates the Lloyd’s market and is ultimately what we are here to do."
Beale previously said insurers could rack up losses of $200bn (£150m) due to the recent storms on the other side of the Atlantic.