Trenwick International Limited (TIL) has been acquired by LCL Acquisitions for an undisclosed fee.
Under the terms of the deal, LCL acquisitions will acquire the entire £75m issued share capital of TIL.
Though the deal has received FSA approval, a number of details need to be finalised before the acquisition is completed.
An LCL spokesman said: "We still have to terminate various relationships, with service companies for example, within the Trenwick Group."
When the acquisition is finalised, LCL will manage the run-off of the entire TIL business for an initial five-year period.
Earlier this month, the management team of Trenwick Managing Agents (TMA) reached an agreement with Trenwick Group to acquire its Lloyd's business.
The management buy-out, which was led by TMA chief executive Michael Watson, included the capture of composite Syndicate 839 and life Syndicate 44.
The new business (NewCo) will be majority-owned by private equity fund Englefield Capital.
The NewCo management team will acquire the TMA business with effect from the 2004 year of account.
In this year of account Syndicate 839 will have a capacity of £250m. Syndicate 44 will have a 2004 capacity of £3.5m.
In February 2003, Trenwick's US stock fell 18.75% after the group revealed losses of $198.1m (£125.7m) for the fourth quarter of 2002.
The losses were seven times greater for the same period in 2001.