ALSO READWall Street ends at record high, led by financial stocks; Apple weighs Wall Street opens higher as tech, bank stocks gain Wall Street edges lower, led by technology and financial stocks Wall Street opens flat amid escalating North Korea-US tensions Wall Street opens higher as energy, financial stocks rise
A bounce in tech stocks, led by Apple and Nvidia, lifted the three major indexes on Tuesday.
Technology stocks had taken a beating on Monday, sliding to their worst daily performance in five weeks, on increasing worries that the top-performing sector was falling out of favour.
Investors are awaiting Fed Chair Janet Yellen's speech later in the day for clues on interest rates.
The Korean peninsula appears to have boosted defences on its east coast, according to a South Korean lawmaker, after Pyongyang said President Donald Trump had declared war and that it would shoot down U.S. bombers flying near the peninsula.
At 9:37 a.m. ET (1337 GMT), the Dow Jones Industrial Average was up 65.45 points, or 0.29 percent, at 22,361.54, the S&P 500 was up 6.34 points, or 0.25 percent, at 2,503 and the Nasdaq Composite was up 30.99 points, or 0.49 percent, at 6,401.58.
Six of the 11 major S&P sectors were higher, with a 0.62 percent gain in the technology sector topping the list.
Energy index though was among the biggest laggards, falling 0.39 percent.
Among stocks, credit reporting firm Equifax fell 1.30 percent after the company said its Chief Executive Richard Smith would retire, in the wake of a massive cyber attack.
Red Hat rose 4.56 percent after the Linux distributor's quarterly profit came in above estimates and the company raised its full-year forecast.
Cleveland Fed Chief Loretta Mester, her Atlanta counterpart, Raphael Bostic, and Fed's Board Governor Lael Brainard are also scheduled to speak later in the day.
Advancing issues outnumbered decliners on the NYSE by 1,585 to 913. On the Nasdaq, 1,448 issues rose and 804 fell.