U.S. hedge fund investor George Soroshas gained about $1 billion since November betting against the yen, the Wall Street Journal reported, citing people with knowledge of the firm's position.
The yen lost nearly 20 percent against the dollar between November and early February, picking up speed as Japan's new government put pressure on the Bank of Japan to ease monetary policy more aggressively to defeat deflation.
Soros Fund Management's internal portfolio, which has been led by Scott Bessent since last summer, holds about 10 percent Japanese shares, the paper reported, citing people close to the firm.
Investors including David Einhorn's Greenlight Capital, Daniel Loeb's Third Point LLC and Kyle Bass's Hayman Capital Management LP, also made big trading profits by riding the yen down, the Journal said.
The Journal did not say how much profit Greenlight, Third Point, and Hayman Capital made on yen trade.
"We put the trades on about three years ago and the trade wasn't fun for the first two years and number of months," Einhorn told the Journal, adding that he expects further weakness.
Investors have wagered against the yen in various ways, from complicated derivatives to simple put options, the kind that Einhorn bought, the Journal said.
Soros Fund, Third Point, Hayman Capital and Greenlight Capital could not be immediately reached for comment by Reuters outside regular U.S. business hours.