The Australian dollar edged higher ahead of US Federal Reserve chairman Ben Bernanke's appearance before the US Congress.
At 1700 AEST on Wednesday, the local unit was buying 92.08 US cents, up from Tuesday's 91.82 cents.
The Australian dollar was at 91.53 Japanese yen, down from Tuesday's close of 91.73 yen, and at 70.12 euro cents, down from 70.18 euro cents.
The currency moved within a tight range, with traders reluctant to sell the higher-yielding unit ahead of Dr Bernanke's semi-annual appearance before an economics committee early on Thursday morning, Australian time.
"It's just being cautious because there is a lot of information that is going to be released tonight," ANZ foreign exchange strategist Andrew Salter said.
"Traders don't want to pre-empt that information by taking positions right now."
But Mr Salter said Dr Bernanke was likely to reiterate his view that quantitative easing (QE) won't be unwound until the Fed's Federal Open Market Committee is convinced the American economy is on the mend.
Any comment from Dr Bernanke supporting stimulus would cause US dollar weakness.
Last week, Dr Bernanke sparked a jump in bond futures contract prices, and a fall in the greenback, after he told a forum in Massachusetts that economic stimulus was still necessary, amid high US unemployment.
In late June, the US dollar rose, causing a fall in the Australian dollar, when he said that QE could end by mid-2014.
Meanwhile, Australian bonds finished flat.
At 1630 AEST the September 10-year bond futures contract was trading unchanged at 96.240 (implying a yield of 3.760 per cent).
The September three-year bond futures contract was at 97.250 (2.750 per cent), down from 97.260 (2.740 per cent).
