The U.S. dollar slumped against the safe-haven yen on Monday on investors’ reduced appetite for risk, while sterling sank to more than two-month lows on talk that Britain would drastically rework trade ties with the European Union after Brexit. A fall in U.S. Treasury yields and U.S. stocks drove the dollar down as much as 0.6 percent against the yen to a session low of 116.16 yen.