Even some of the smartest guys in the room got this one wrong.
The billionaire hedge fund manager Leon Cooperman told an audience of Wall Street insiders on Wednesday that there was a 70 percent probability that Britain would stay inside the European Union. "I don't worry about Brexit," he added.
Two weeks earlier, , who became known as the man who broke the Bank of England with a bet against the British pound in 1992, said he was "confident that as we get closer to the Brexit vote, the 'remain' camp is getting stronger."
"Markets are not always right, but in this case I agree with them," Mr. Soros added.
Then on Thursday, the British electorate voted to leave. The reaction in markets was swift and violent: Stocks around the world went into free fall, the British pound sank to a more than 30-year low against the dollar, and central banks pledged to provide emergency help.
Ben Hunt of Salient Partners, went as far as to call it a "Bear Stearns moment," evoking the investment firm whose collapse in March 2008 was a prelude to the financial chaos that September.
Yet even as the most successful hedge fund managers now survey a sea of down markets, panic has not gripped the industry. That's because many hedge fund managers watched the elections from the sidelines. Any winners and losers will be determined in the days and weeks after the vote.
"We're not in panic mode. We're just trying to get a sense of things," said Hans Humes, who runs Greylock Capital, a hedge fund firm that specializes in distressed bonds, adding that Greylock did not make any bets on the Brexit poll.
"There was a ton of cash on the sidelines," he added.
Britain's vote to leave the European Union poses difficult questions for investment firms like Greylock, which made big bets on Greece as it teetered on the brink of economic collapse. At a time when many European countries are dealing with flagging economies, Mr. Humes said he was concerned that the Brexit vote would feed a growing populist surge across the Continent, threatening to chip away at the foundation of the European Union.
Other managers sold their risky assets as the markets climbed higher ahead of the vote in anticipation of a "remain" vote, said Troy Gayeski of SkyBridge Capital, a $12.5 billion firm that invests in hedge fund portfolios.
"Very few, if any, were so convinced that Brexit was going to happen that they would risk enough capital to make money from it," he said.
Jason N. Ader, chief investment officer of the hedge fund SpringOwl Asset Management, said his firm bet against a basket of companies with high exposure to the British pound going into the poll on Thursday to counteract a potential hit to one of his firm's biggest investments, in GVC Holdings, a British online-gambling company.
As to whether he planned to make any fresh bets after the vote, Mr. Ader said, "This will take a long time to shake out."
It may not be surprising that a number of hedge funds are proceeding with caution. The last major episode of market turmoil, when Chinese stocks tumbled last summer, sent many hedge funds reeling. Some have yet to recover.
Even as few major winners have emerged, anyone who had large holdings in safe havens like Treasury securities and gold — which rose sharply on Friday — looked smart the day after the vote. That includes Mr. Soros, who told The Wall Street Journal that he didn't think a Brexit was likely in an interview just a few weeks ago. His Soros Fund Management has taken long positions in gold through an exchange-traded fund, according to recent regulatory filings.
More from the New York Times:
'Brexit' Revolt Casts a Shadow Over Hillary Clinton's CautiousPath
Donald Trump, in Scotland, Calls 'Brexit' Result 'a GreatThing'
Turbulence and Uncertainty for the Market After 'Brexit'
Whether Mr. Soros took any positions to profit from a Brexit is unclear. A day after the referendum, he warned of the consequences of the Brexit vote.
"The consequences for the real economy will be comparable only to the financial crisis of 2007-2008," he wrote in a post on the opinion website Project Syndicate.
Mr. Cooperman, who cited optimistic figures about the "remain" vote, also sounded a cautious note when he spoke at a Youth INC charity event at the Metropolitan Club in Manhattan on Wednesday.
"I think Brexit is going to have a very negative impact on Europe if it happens," Mr. Cooperman told an audience of investment professionals.
By Friday, he had adopted a darker view.
"My friend at Microsoft was dead wrong, as was I," Mr. Cooperman said, referring to the source of his optimistic probability of Britain's voting to remain. "This, too, shall pass."