Credit Suisse First Boston is losing one of its two co-heads of European mergers and acquisitions to UBS Warburg's US business.

James Neissa, previously co-head of European M&A at Donaldson, Lufkin & Jenrette with Margaret Young until CSFB acquired the bank last year, is to become co-head of US M&A at UBS, according to insiders. He will work alongside Richard Leaman, the present head of US M&A.