Most economists doubt Donald Trump's ability to foster economic prosperity,  but activist investor Carl Icahn is far more optimistic. 

"Donald is going to surround himself with some very good people," Icahn, a longtime Trump supporter, reportedly said of the president-elect at a Reuters Global Investment Outlook Summit Wednesday. He added, in reference to the president responsible for passing the 1964 Civil Rights Act, which barred discrimination on the basis of race and sex: "He'll be a guy to do what you need to build consensus. He'll do it like Lyndon Johnson did it."

The activist investor, who has previously been floated as a possible treasury secretary in a Trump cabinet, expressed his satisfaction with the fact that a corporate executive and Washington outsider would be occupying the Oval Office.

“We have a perception that the government is at war with business,” he said at the Reuters summit, adding that he was confident that Trump could move the U.S. economy past its period of “stagnation”—a result of “establishment” figures holding power in Washington—and reverse regulations like the Dodd-Frank Wall Street Reform Act that “went too far.” “The point I think about Donald is he’s a consensus builder, he’s a very smart guy.”

Icahn has made billions predicting stock market movements—in the early morning after Election Day, he confirmed on his way out of President-elect Donald Trump’s victory party that he had made a billion-dollar bet on plummeting U.S. equities, only for them to rally the next day.

As for the future of the stock market under Trump, Icahn, known for his 1986 takeover of Trans World Airlines, believes the stock market’s post-election boost was a bit overblown, but that investors shouldn’t be too worried.

“When it runs up like this, I scale off a bit,” he said. “But that doesn’t mean that I am that negative or positive.”

Icahn's comments came the day after he tweeted an endorsement of two of Trump’s transition team’s picks for secretary of the Treasury and Commerce departments.

A fellow corporate magnate from Queens, Icahn has a relationship with the president-elect that spans decades, with the former often rescuing the latter from bankruptcy. While Icahn told the Washington Post in April that he was "not here to say that Donald's a great businessman," his more recent commentary on the soon-to-be-president's corporate acumen has been far more favorable.

In an interview with CNN’s Poppy Harlow Saturday, Icahn defended Trump’s potentially-damaging plans to impose tariffs on companies using inputs in their products produced abroad, as well as broader tariffs in general, under Trump's plans to end American participation in major free trade agreements and organizations. Icahn argued that those inputs were inferior to American-made alternatives.

“If you’re importing a lot of goods from China and some of these goods, really, if you compare them to American goods, not all of them, but some of them are inferior—I think there’s going to be pressure on some of those companies,” he said, listing automakers with imported brakes as possible losers in a Trump presidency. “I think you’re going to see a lot more manufacturing done in this country.”

As for the winners, Icahn listed, “smart businesses, guys that are willing to invest, guys that are willing to take the chance, and will invest when they get better breaks from the government.”

Trump’s business policies involve a massive reduction in the corporate tax rate to 15 percent from 35 percent, as well as scrapping the Environmental Protection Agency’s carbon emissions-reducing Clean Power Plan and the Waters of the United States rule under the Clean Water Act. 

When it comes to stock market performance under President Trump, Icahn may not be alone in terms of his bullishness, according to a study from UBS Wealth Management released Thursday. Of 1,200 investors surveyed by financial services company, the proportion who felt optimistic for the future of the U.S. economy jumped 9 percentage points, to 48 percent from 39 percent.

Those investors, along with Icahn, may be anticipating the implementation of yet another Trump tax policy that could give their unearned income a bit of a boost. The president-elect plans to remove a 3.8 percent net investment income tax that President Barack Obama instituted as part of the Affordable Care Act in 2013.