“In my mind, it is time to be cautious about the U.S. stock markets,” Icahn said in a telephone interview. Icahn has been pressuring discount retailer Family Dollar Stores Inc to sell itself. On Thursday, Family Dollar said its profit fell by a third as it cleared inventory ahead of planned store closures and competition intensified. Icahn, Family Dollar’s largest shareholder with a 9.4 percent stake, wants the company to sell itself to rival Dollar General Corp to help them cope with stiff competition from big-box retailers such as Wal-Mart Stores Inc.