The stock market would have some "setbacks" if President Donald Trump and the Republicans on Capitol Hill are unable to deliver on the promises of broad tax reform and "true deregulation," BlackRock Chairman and CEO Larry Fink told CNBC on Thursday.

"If you believe it will be longer for these [policies] to transpire — and we have an economy that's slowing because of uncertainty — then I would say the U.S. equity markets are probably higher than they should be," Fink said on "Squawk Box."

BlackRock, the world's biggest money manager, has $5.1 trillion in assets under management.

The U.S. will likely have the slowest first-quarter economic growth of all the G-7 nations, Fink said, predicting a gross domestic product print of under 1.5 percent.

Fink cited the hotel industry as an area of weakness due to fewer tourists in the United States, which he blamed on Trump's immigration policy for making people from some parts of the world feel unwelcome. "There's [also] a drop of 20 to 40 percent of foreign applications to our universities," Fink said.

U.S. stocks would come under pressure if the American economic growth slows, he said, adding European stocks are a better value right now than U.S. stocks.

Fink sees only one or two more interest rate hikes this year instead "three or four" total increases in 2017.

The minutes from the Federal Reserve's meeting in March — when policymakers last hiked rates — sparked the Wednesday afternoon stock sell-off. The market were rattled by the Fed's comments about reducing the central bank's $4.5 trillion balance sheet more quickly than investors had anticipated, as well as remarks about high equity valuations.

Wall Street on Wednesday saw its biggest intraday reversal in 14 months, with the Dow Jones industrial average giving back a nearly 200-point gain to end the day lower.

Read more from Fink's interview: