The S&P500 has extended gains to a fourth day, putting it on the cusp of a new five-year high if Friday's jobs report shows encouraging signs for the labor market.

Some analysts credited Mitt Romney’s strong presidential debate performance against Barack Obama for the gains.

Gains were evenly spread through sectors, with trade strongest in Bank of America, which gained 3.4 per cent, and Apple, which lost 0.7 per cent.

At the closing bell, the blue-chip Dow Jones Industrial Average was up 80.75 points (0.60 per cent) at 13,575.36.

The broad-based S&P 500 added 10.42 points (0.72 per cent) at 1460.41, and the tech-rich Nasdaq Composite gained 14.23 (0.45 per cent) to 3149.46.

Romney, the Republican challenger for the White House favoured by business and investors, boosted his chances late on Wednesday as he outperformed President Obama in the first of three presidential debates, which covered the economy.

‘‘Some market watchers might be inclined to tie the bounce to the successful debate performance last night by Mitt Romney. Political pundits largely agree that Mr Romney won last night’s debate,’’ said Patrick O’Hare of Briefing.com.

But, he said, ‘‘If anything, the upside bias is largely a product of more of the same: performance chasing’’ as well as faith in the Federal Reserve’s newest QE3 stimulus.

‘‘The upside bias remains intact at this juncture with the S&P futures trading 0.5 percent above fair value,’’ O’Hare said.

AFP, Reuters