Global stock markets are plunging Wednesday as investors move their money into safe havens like gold as traders react to an impending Donald Trump presidency.

World markets were wildly volatile through election night in the U.S., with stocks, currencies and bonds swinging as investors factored in the reality that the Republican businessman could best Democrat Hillary Clinton in the 2016 U.S. presidential race. Trump, who has never held public office, defeated Clinton to be elected the 45th president of the United States on Wednesday, the Associated Press reported. Wall Street had been pricing in a Clinton win.

Japan's Nikkei 225 plunged 5.4% while Hong Kong's Hang Seng index lost 3.2% Futures on the Standard & Poors 500 index hit a trading halt designed to limit losses and were recently down more than 4%.

The Dow Jones industrial average was down about 638 points, or 3.4%, in futures trading. If the Dow's losses stick when regular trading resumes Wednesday, the point loss would top the 610-point drop back on June 24, when the United Kingdom voted to exit the European Union, a crisis known as Brexit. The Dow's current level would also challenge the record one-day plunge of 777.68 points back on Sept. 29, 2008, during the financial crisis.

“What the market is telling us is that all of a sudden the chance of a Trump win is very real,” says Brad McMillan, chief investment officer at Commonwealth Financial Network. “Trump winning introduces a lot of policy uncertainty,” on issues ranging from trade to immigration to tariffs.

Investors are rushing into perceived havens, such as gold, which is up $40 an ounce, or 3.1%, to $1314.

In a similar sign of investor angst as the votes are counted, U.S. Treasury yields, which move opposite price, were slipping. The yield was lower at 1.811%, after being as high as 1.889%.

The Trump strength in this election is similar to what happened during the surprise Brexit vote, which was characterized by untrustworthy polls, rising populism and an angry electorate.

Says Craig Erlam, senior market analyst at OANDA: " It’s been a bloodbath in the markets ... as Donald Trump edges ever closer to the White House. The way markets have traded over the last couple of days and positioned ahead of the vote, you would think the election was going to be a routine victory for Clinton despite her name being dragged through the mud during the FBIs email investigation and the anti-establishment protest vote becoming ever more prevalent around the globe. Brexit should have been a warning for the markets and instead, it appears four months is more than long enough for such a historic even to be forgotten."

What really has Wall Street worried, McMillan adds, is the prospect of a so-called Republican "sweep," in which Trump wins the White House and the GOP retain control of both the Senate and House. “A Republican sweep gives Trump a lot more policy flexibility than a divided government would,” says McMillan.

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