Bad weather and weakness in specialist commercial lines caused a 19% drop in UK insurer RSA's full-year operating profit, sending its shares lower today. 

Insurers globally have suffered from two years of heavy losses after natural catastrophes such as storms, hurricanes and typhoons.

Premium increases across a range of insurance classes have also been capped by strong competition.  

"We had subsidence in the summer in the UK, the "Beast from the East" in the winter in the UK, Canada had lots of weather losses," CEO Stephen Hester told a media call after the group's results. 

Overall, 2018 was "the fourth worst year globally for things like hurricanes, which is part of the international losses," he said. 

Stephen Hester said changes to the business would help to ensure a "bounce back" for the group in 2019, but the group's shares fell more than 3% today. 

The insurer warned last year about poor performance in its London-based international commercial insurance business and pulled out of several lines, including international freight and construction. 

It put former finance head Scott Egan in charge of the UK and international business earlier this month and said today its London market business was undergoing a strategic review "to identify any further portfolio exits". 

Operating profit for the year ending December 31 fell 19% to £517m, below the £561m forecast in a company-supplied poll. 

Underlying profit fell 33% to £250m and underlying return on tangible equity dropped to 12.6% from 15.5%, below the company's 13-17% target range.

The insurer said it would pay a total dividend of 21 pence per share, up 7% and in line with forecasts. 

Rivals Lloyd's of London insurer Hiscox reported a beat on pre-tax profit earlier this week, while motor insurer Hastings today also saw a rise in pre-tax profit.