Billionaire buy-and-hold investor Ron Baron told CNBC on Friday he's losing sleep over the presidential election.
"For weeks now, I'm been so upset with this election. I wake up every night two or three times; 2 o'clock in the morning, 4 o'clock in the morning. I go to my phone to see what's happening, the odds," Baron said on "Squawk Box."
"There's tremendous uncertainty created by the candidates here, one especially," he said. He declined say which candidate he was referring to but hinted that it was Donald Trump.
"Because of that, if the election goes one way or the other, there's going to be a real tough time for businesses for a while," the founder of Baron Capital said. "That may be reflected in stocks. It may not be."
"It's hard to invest when you don't have confidence in what the policy is going to be," he said from on the sidelines of the annual Baron Investment Conference in New York. "The economy could struggle a little bit if that happens."
Ahead of Friday's trading, the was about 1 percent below the close on June 7. Presidential election concerns have recently hit Wall Street as Democrat Hillary Clinton's lead over the GOP nominee narrows.
The index on Thursday logged its eighth-straight down session, the longest daily losing streak since October 2008.
But on a percentage basis, the decline only accounts for a 2.9 percent loss. The October 2008 stretch saw the S&P drop 23 percent. A ninth-straight down session Friday would be the first daily losing streak of that length in nearly 36 years.
More from the Baron Investment Conference:
Billionaire Ron Baron tells investors how they can beat computer traders
Donald Trump's character reflects poorly on United States, Elon Musk says
Musk: Raising cash as buffer may be desirable
— Tesla's Elon Musk joins Ron Baron on CNBC from the Baron Conference for an interview at 11 a.m. ET on "