Investors bid up a number of stocks following earnings reports, including Salesforce, up 1.5 percent, Deere & Co., up 7.8 percent and Applied Materials, up 0.7 percent.

Energy shares rose on higher oil prices, with Halliburton and Devon Energy both gaining 1.5 percent.

Analysts also cited the relatively placid news flow over the last 24 hours involving Trump after a number of shocking stories involving Trump in the last week over the firing of FBI director James Comey and allegations the president disclosed highly sensitive intelligence to Russian officials.

Trump is leaving Friday for an eight-day swing through the Middle East and Europe, "so there is also a budding sense that the stock market might get a measure of relief in the near term from the political drama unfolding here at home," said Briefing.com analyst Patrick O'Hare.

But he cautioned, "One shouldn't be surprised if that assumption ultimately gets nipped in the bud."

About 15 minutes into trading, the Dow Jones Industrial Average stood at 20,718.63, up 0.3 percent.

The broad-based S&P 500 rose 0.4 percent to 2,375.25, while the tech-rich Nasdaq Composite Index advanced 0.6 percent to 6,089.89.