The Dow Jones Industrial Average, the most closely watched U.S. stock index, closed above 20,000 for a second day Thursday.
The Dow advanced above 20,000 for the first time ever Wednesday. The buoyant U.S. market boosted Asian stocks Thursday, with Japan's Nikkei up 1.8 percent by the close, while Hong Kong's Hang Seng rose 1.4 percent. Other major indexes on U.S and European markets were mixed at the end of Thursday's trading.
President Donald Trump's actions are encouraging to investors, according to CFRA Research chief investment strategist Sam Stovall.
"I think it was the first two days of President Trump issuing a lot of executive orders, and that pretty much told Wall Street that he really is going to attempt to fulfill the promises he made during the campaign," Stovall said.
University of Maryland international business professor Peter Morici says the Trump effect may push inflation up a little faster.
"I think we'll be above 2 percent for a while, and I think the Fed [U.S. Central Bank] will be gradually raising interest rates, half a percentage point, three-quarters of a percentage point a year," he said.
Analysis by the Wall Street Journal showed some experts worried that the recent surge in stock prices has a "fragile economic foundation," and called this a "time for caution."