Dow industrials and S&P 500 rose on Wednesday despite a rise in oil prices after moves by central bank efforts to boost liquidity in financial markets.
The US Federal Reserve and other central banks said they would boost measures to stabilize financial companies struggling with credit losses.
However, the price of oil rose by nearly 4% after inventory data showed a decline in gasoline stockpiles.
A private-sector employment report showing employers added 9,000 jobs in July - raising hopes for a stronger-than-expected government jobs report on Friday.
The Dow Jones industrial average shot up 186.13 points, or 1.63%, to 11,583.69.
Standard & Poor's 500 Index advanced 21.06 points, or 1.67%, to 1,284.26. The Nasdaq Composite Index gained 10.10 points, or 0.44%, to 2,329.72.
Trading volume was light on the New York Stock Exchange, with about 1.47 billion shares changing hands. Volume was high on the Nasdaq, with about 2.27 billion shares traded.
European shares up also
European shares ended sharply higher on Wednesday after upbeat results from Siemens and ArcelorMittal.
ArcelorMittal, the world's No. 1 steelmaker, reported record second-quarter results. The DJ Stoxx basic material index rose 4.4%.
Shares in Siemens were up 5.8% after the engineering group posted stronger-than-expected third-quarter results.
Tthe pan-European FTSEurofirst 300 index ended up 1.6% at 1,180.75 points, after rising 0.3% in the previous session.
In Britain, the FTSE 100 closed 101.5 points higher, 1.91%, at 5,420.7.
Markets also drew support from a move by central banks in the United States, Europe and Swiss to extend liquidity offerings to stressed banks and securities firms.
Financial stocks gained with HSBC up 2.7%, Royal Bank of Scotland up 3.9% and BNP Paribas gaining 2.3%.
NZ & Australian markets
The NZX 50 index rose 52 points on Wednesday to close at 3288 on turnover of $84 million.
Telecom was up 7 cents to $3.66, Contact Energy was up 12c to $8.32 and Fletcher Building was up 9c to $6.34.
Auckland International Airport was up 7c to $1.75 after Macquarie Bank disclosed it has taken a 5% stake in the airport.
The dollar was buying 73.83 US cents, 77.70 Australian cents, 37.23 pence, 79.71 yen and 0.4732 euro. The Trade Weighted Index was 66.16.
The Australian share market ended the day on a high note. The S&P/ASX200 index was up 89.2 points, or 1.84%, to 4936.7, while the All Ordinaries climbed 85.4 points, or 1.73%, to 5008.7.
The September share price index futures contract was up 88 points to 4915 on a volume of 17,443 contracts.