A heavy day of earnings releases included strong reports from Dow members Coca-Cola and United Technologies, which jumped 4.8 percent and 1.6 percent respectively.

Others that rose following earnings included toy company Hasbro, biotech company Biogen and paint company Sherwin-Williams, while insurer Travelers and motorcycle company Harley-Davidson both dropped.

About 20 minutes into trading, the Dow Jones Industrial Average stood at 27,263.42, up 0.3 percent.

The broad-based S&P 500 had also gained 0.3 percent, rising to 2,993.50, while the tech-rich Nasdaq Composite Index had added 0.2 percent at 8,219.77.

Analysts also pointed to relief after President Donald Trump and congressional leaders agreed to a bipartisan budget agreement that will boost federal spending by $320 billion and suspend the debt limit beyond the next presidential election.

The deal, should it pass Congress as expected, would allow the federal government to borrow more money and avoid a disastrous default in the coming months, while significantly raising budget caps on defense and domestic outlays.

Briefing.com analyst Patrick O'Hare said the market was not "overly concerned" about the state of play on the budget but added that the agreement "is an incremental positive in that it should eliminate any eleventh-hour drama involving the debt ceiling when September rolls around."