The Italian family that controls Cushman & Wakefield Inc., one of the world's largest real-estate services firms, is putting the company up for sale as rising property prices push up the value of rivals, according to people familiar with the matter. Exor SpA, the investment arm of the Agnelli family, has approved management's hiring of Goldman Sachs Group Inc. and Morgan Stanley to help look for a buyer for Cushman, the people said.