Traders said the talk was that that the Fed would cut interest rates when it released its new growth forecasts and the minutes from its October meeting at 1900GMT.
The dollar fell 1 per cent to an all-time low of $1.44813 against the euro, dropped 0.8 per cent to $2.0650 against the pound and lost 0.8 per cent to SFr1.1070 against the Swiss franc.
Neil Mellor at Bank of New York Mellon dismissed the speculation, however.
The Fed will want to keep its options open,” he sad. By introducing an emergency rate cut, it would send the wrong message out to the market and seriously undermine its credibility.”