Marsh and Thompson Heath and Bond (THB) will share the broking of the 2005 British Lions tour.
A spokesman for THB confirmed that the company had won the personal accident account for the tour of New Zealand. He said the account had previously been with Marsh.
But Marsh has retained the right to place some of the other covers for the forthcoming tour, he added.
Marsh declined to comment on the account.
Former England coach Sir Clive Woodward will lead the Lions tour.