NEW YORK (MarketWatch) -- Greenlight Capital manager David Einhorn said Monday that his hedge fund firm is betting on the possibility of a major currency collapse and a surge in interest rates, citing ballooning government deficits in some of the world's most developed countries. Einhorn said Greenlight has been buying long-dated options on much higher interest rates in Japan and other developed regions, giving the firm the chance to make big profits from a jump in rates. The options, bought from major banks, are tied to interest rates four to five years out, Einhorn noted. In the case of Japan, rates have been very stable in that country for many years, so the options were relatively cheap. Einhorn said the "asymmetry" of that trade was interesting. If rates jump suddenly in Japan, Greenlight stands to make "multiples" on its positions, he added.