General counsel of GIB UK Dominic Bacon is leaving to join online retail spreadbetting company CMC Markets.
CMC, which specialises in foreign exchange and contracts for difference, was established in 1989 and has 10 offices worldwide.
Bacon said: "CMC is in growth mode and the business area it's in is a growth area."
CMC is understood to use CMS Cameron McKenna, among other firms. As general counsel Bacon will inherit a legal capability that includes three UK lawyers, four compliance officers and three overseas lawyers in Canada and Germany.