The planned return of trading on Wall Street after a two-day suspension due to superstorm Sandy helped financial markets edge higher in Europe and Asia on Wednesday.
The New York Stock Exchange was closed on Monday and Tuesday as the storm hit the city, leaving scores dead and a massive clear-up operation.
With the New York subway still down and a backlog of corporate earnings due for release, trading could be erratic.
The volatility could be enhanced by the fact that it is the last day of the trading month, when many investors close out positions and try to improve their accounts.
"The first few hours are likely to be manic with the US markets still to factor in corporate earnings from the start of the week and the effects of the hurricane among other things," said Craig Erlam, market analyst at Alpari.
In Europe, Germany's DAX rose 0.6 per cent to 7,330 and the CAC-40 in France was 0.4 per cent higher at 3,473. Britain's FTSE 100 was down modestly at 5,840.
In the US, Dow futures and the broader S&P 500 futures pointed to 0.5 per cent gains at the opening bell.
There's a raft of US economic news to be released over the coming days, culminating in Friday's nonfarm payrolls data, which often set the market tone for a week or two after their release. This time they may have a more notable impact as they come days ahead of the country's closely-fought presidential election.
In the currency markets, the euro managed to brush off figures showing unemployment in the 17-country eurozone climbed to a record 11.6 per cent in September.
When the appetite for risk among investors increases, as evident in the rise of stock markets, traders often buy the euro and sell the dollar. By late morning London time, the euro was 0.4 per cent higher on the day at $1.3020.
Oil prices though were flat with the benchmark New York rate unchanged at $85.54 a barrel.
Earlier in Asia, Japan's Nikkei 225 stock index closed 0.1 per cent lower at 8,928.29 while Hong Kong's Hang Seng index rose 1 per cent to 21,641.82. Mainland China's main index in Shanghai close 0.4 per cent higher at 2068.88.