The strongest buying has been from foreign central banks investing the dollars they had bought.

With the earnings season drawing to an end, Wall Street will need another catalyst to inspire more strong buying.

Foreign exchange dealers said the dollar was first helped by strong Japanese buying.

"We saw strong buying in Mexico today not only by hedge funds, but also some of the big mutual funds."

The last 10 days have seen two corrections to the rally, "but both were met with very strong buying and immediately rebounded," he said.

There has been some extra strong buying from Japan, which we think is just inventory building.

Trading, at 303.4 million shares, was the seventh-heaviest on record and a sign of strong institutional buying.

Currency dealers said technical factors dominated trading in the absence of any strong buying or selling incentives.

Traders took their cue from strong buying in Asia and Europe.

The results touched off strong buying of Chrysler stock.