Rj Kiln & Co has taken over medical malpractice liability syndicate 1204 from Crowe, two days after announcing it intended to increase its Lloyd's underwriting capacity by £160m.
Kiln and Crowe had signed initial agreements in July, but only completed negotiations on October 19.
Kiln has assumed management of 1204's underwriting and administration for business in 2000, 2001 and the future, in return for a profit share and fee.
The 1204 team, led by underwriter Janet Helson, has moved into Kiln's Fenchurch Street offices in London.
Kiln managing director Edward Creasy said the successful transfer meant Kiln had fulfilled the first part in its strategy to manage a number of specialist syndicates with funding from the international insurance community.
Two days before the negotiations with Crowe were finalised, Kiln announced it would not make cash calls on Lloyds' Names over its World Trade Centre losses.
Instead, it is "exploring alternative options" on how it will substantially increase its underwriting capacity for 2002 from £340m to £500m.
A spokesman said this was needed to "take full advantage of the extraordinary opportunities, both present and future".
The increase will bring forward Kiln's capacity target by two years.
Kiln has predicted its composite syndicate 510, which accounted for 80% of its underwriting activity this year, will remain profitable.
Syndicate 1204 has £23m underwriting capacity for the 2001 year of account.