The two top reinsurance executives with Bermuda-domiciled Torus Insurance Holdings Ltd are leaving, the company has confirmed.Bermuda-based Tim Mardon, the group's president and chief underwriting officer of reinsurance, is set to rejoin his former employer, Ace Tempest Re, which is also based on the Island.Also leaving is Mr Mardon's number two Jon Sullivan, who is based in the UK, having relocated from Bermuda two years ago to open Torus Re's office in London.Torus confirmed on Friday that both men were leaving, but added that the company would continue to write catastrophe reinsurance in Bermuda, as well as London. Its senior casualty underwriter David Whiting continues to be based in the Bermuda office.“Both Tim and Jon are recognised experts in catastrophe reinsurance,” Torus CEO Clive Tobin said. “On the back of recent events they have been offered attractive opportunities to manage larger catastrophe portfolios.“Torus' strategy has been to build a diverse book of specialty business weighted predominantly in insurance with a niche portion of our overall portfolio coming from reinsurance. We continue to pursue that strategy.“We are very pleased with the overall performance of our catastrophe book. Market data released independently of Torus highlights a positive performance compared to others in the market during the events of the first quarter of 2011.”Torus was launched in Bermuda three years ago. It has grown into a global insurance and reinsurance company with more than 600 employees in 13 offices in Bermuda, Europe and the US.In late 2008, the company bought the Bermuda reinsurance operations of hedge fund Citadel, New Castle Re and CIG Re. Mr Mardon moved to Torus from New Castle Re.Torus's Bermuda office has focused solely on reinsurance since March, when the group's excess liability operation on the Island was closed down.Privately-held Torus, which is heavily backed by First Reserve, has had mixed underwriting fortunes. At a conference in June, Mark McComiskey, a managing director at First Reserve, said Torus had an excellent 2009, when its loss ratio was 31 percent. However, in 2010, the loss ratio climbed to 76 percent against an industry average of 56 percent, as the company's heavy weighting of energy in its portfolio cost it dear in the year of the Deepwater Horizon oil rig loss.However, Mr McComiskey added that in the first five months of 2011, which were marked by catastrophes including earthquakes in Japan and New Zealand and flooding in Australia, major-event losses had totalled $69 million. Equivalent to 7.3 percent of its book value, the figure was below an industry average of 9.8 percent.