For the past few years, one of the most common refrains from hedge fund managers was that the main drivers of the market were the Federal Reserve and other central banks. A number of managers complained, even as stocks rose, that the Fed’s low interest rates were distorting markets. (The fact that hedge funds have badly trailed the market for the past few years perhaps fueled those complaints.)

But according to Dalio, who runs Bridgewater, the world’s largest hedge fund firm (and whose own performance has been mixed over the last two years), the Fed’s reign over the markets is over. In 2017 and perhaps beyond, the most powerful force driving the market will be populism, he says, and he’s terrified.

“Populism is the No. 1 economic issue that market participants should be watching, more important than central banks,” said Dalio. “I want to be loud and clear—populism scares me.”

Dalio said he was scared of populism because it leads to extremism—potentially leading to attacks on the 1%, of which Dalio, a billionaire, is squarely a part. But he also implied that populism has the power to distort markets. With populist political movements, Dalio said, it’s not always clear who the policymakers will be. And as policymakers change, so too, obviously, will policy and its impact on the markets.

It’s not that surprising that someone embedded in the financial establishment would be worried about a grassroots uprising of the middle and working classes. Still, Larry Summers, the economist and former advisor to Obama, threw some cold water on the idea that Trump’s brand of populism would take aim at Dalio and other one-percenters. He said it was unlikely the American populace would have hired “the world’s most visible symbol of conspicuous consumption” as president if they were really worried about the wealthy.

But Summers did agree that investors may be too complacent about populism, and he backed up Dalio’s notion that Trump’s tweets and comments could have an outsized impact on investors’ portfolios. “I would be cautious about predicting that Trump will somehow awake businesses’ animal spirits,” said Summers. “When Trump makes ad hoc comments about drug companies, and the value of those stocks plunge $45 billion, I am not sure how that is good for business confidence.”

Even in Davos, which isn’t a very pro-Trump gathering, it appears that the consensus is that the President-elect’s populist policies will boost the U.S. economy. But at the same time, it gives Dalio, and hedge fund manager like him, a new bogeyman.