Technology stocks boosted the Nasdaq to a record at the open on Wall Street, while encouraging results from some retailers and Medtronic helped bolster the gains.
As the third-quarter earnings season winds down and with no major economic data scheduled for the week, trading volumes were thin and expected to get even quieter in the run-up to the Thanksgiving holiday.
Also helping the market was a slight rise in oil prices ahead of next week's OPEC meeting at which major crude exporters are expected to extend production cuts.
A dip in the dollar index, after a strong gain on Monday, also eased the pressure on commodities. A lower dollar helps US multinationals increase the value of overseas income.
The Dow Jones Industrial Average was up 133, or 0.6% at the open at 23,563. The S&P 500 was up 12 points, or 0.5%, at 2,595 and the Nasdaq Composite was up 40 points, or 0.6%, at 6,831.
All the 11 major S&P indexes were higher, led by gains in the technology index, which is the best performing sector this year.
Apple's shares were up 1.1%, boosting all three major indexes.
Medtronic rose 5%, making it the top gainer on the S&P 500, after the medical device maker reported better-than-expected results and backed its forecast.