Recently, the company made its move into live underwriting with the planned acquisition of Atrium Underwriting Group and Atrium's reinsurance business, Arden Reinsurance Co., for $263 million.

Enstar expects to complete both the Atrium and Torus transactions by the end of this year.

The private equity company Stone Point Capital is backing the acquisition, supplying $277 million in capital. At the close of the transaction, Enstar will own 60 percent of Tours and Stone Point will own 40 percent.

The major shareholders of Torus, the private equity firms First Reserve and Corsair Capital, will receive a combination of Enstar shares and cash. The remaining Torus shareholders will receive cash.

As for the change in management, Tobin says he is leaving as “the company entered the next stage of its development and this is the appropriate time.” Tobin joined Torus in 2009 as CEO after working for a number of years at XL.

O'Donohoe joined Torus in 2009 as chief underwriting officer, global specialty and chief operating officer of Torus in the United Kingdom and Europe. He became chief executive of Torus International in 2011. He has more than 25 years of insurance experience across international and Americas markets.