Credit Suisse has hired a new head of equities from UBS, hoping to reinvigorate its stock-trading business and better ply that service to global billionaires.

Michael Stewart will join the Swiss bank to run equities in its global markets business, the core of its trading operation, according to a memo reviewed by The Wall Street Journal. He currently sits at the intersection of UBS's massive wealth management franchise and its securities division, helping to bring the type of institutional level trading to wealth clients.