A roundup of trading on major world markets:
NEW YORK - US stocks opened modestly higher with markets mostly tentative ahead of Federal Reserve Chair Janet Yellen's testimony in Congress on Thursday.
Fifteen minutes into trade on Wednesday, the Dow Jones Industrial Average was up 12.33 points (0.08 per cent) at 16,191.99.
The broader S&P 500 gained 1.68 (0.09 per cent) at 1,846.80, while the Nasdaq Composite rose 13.44 (0.31 per cent) to 4,301.03.
LONDON - Russia's ruble has fallen to a record low over the Ukraine crisis and concerns over growth, while European shares have dipped on profit-taking and waiting for cues from the United States.
The Ukrainian hryvnia fell to a record low of 10.40 to the US dollar on Wednesday, continuing a slide that has seen it lose 18 per cent of its value since the start of the year.
The FTSE 100 index in London's stock market shed 0.46 per cent to 6,799.15 points, the DAX 30 in Frankfurt gave up 0.38 per cent to 9,661.73 points, and Paris's CAC 40 lost 0.40 per cent at 4,396.91 points.
Much of the focus in European stock exchanges was on profit-taking after bumper runs, though traders were also awaiting direction from the United States, which has given some mixed data so far this week.
Federal Reserve head Janet Yellen is due to testify on the state of the US economy to Congress on Thursday.
The euro slipped to 1.3664 to the dollar, from 1.3744 late on Tuesday.
HONG KONG - Asia's markets mostly rose as investors brushed off a weak batch of data from the United States, while the US dollar edged up against the yen.
Tokyo dived more than one per cent at the open on a stronger yen. But the market later picked up, in line with a greenback revival, and by the end of trade the Nikkei was 0.54 per cent, or 80.63 points, lower at 14,970.97.
Seoul rose 0.30 per cent, or 5.91 points, to 1,970.77 and Sydney closed flat, edging up 3.2 points to 5,427.0.
Shanghai added 0.35 per cent, or 7.04 points, to 2,041.25, following recent losses caused by liquidity fears and concern about possible moves to rein in property prices.
Hong Kong ended up 0.54 per cent, or 120.24 points, at 22,437.44.
WELLINGTON - The NZX 50 Index rose 5.687 points, or about 0.1 per cent, to 4973.198.