Investors bet one of the biggest trades on Wall Street will unwind

- The Japanese yen has plunged to a 20-year low, prompting some to wager that the Bank of Japan won’t be able to stick to its ultraloose policy
The rapid fall in the Japanese yen has been at the center of one of the biggest bets on Wall Street this year. Now a group of contrarian investors is pushing in the other direction, expecting a major reversal.