What to Know
Dow futures plunged as much as 800 points before rebounding
Markets were betting on a Clinton victory and were surprised by Trump's strength
Asian markets also sank and investors rushed into safe-haven bets like gold and U.S. government bonds
Stock market futures plunged dramatically Election Night, as investor expectations of an easy Hillary Clinton win ran head-long into a Donald Trump victory.
Futures on the Dow Jones industrial average - used in part to bet on the next session's open - fell more than 800 points at one point on the night. In its history, the Dow has never lost that much in a regular trading session.
By 2:50 a.m. ET, when Trump accepted Clinton's concession, the Dow had made back almost half those losses.
Futures for the tech-heavy Nasdaq and the benchmark S&P 500 index went "limit down," meaning they had fallen so much (roughly 5%) that by rule they could not trade any lower for the night.
A market volatility index known as the VIX - also sometimes called the "fear index" - rose 40 percent.
The election uncertainty also jolted currency markets, sending investors fleeing from the dollar. By late Wednesday Tokyo time, the dollar was at 103.36 yen, down 1.5 percent from 105.46 earlier in the day. The euro rose to $1.1115 from $1.1020. The Mexican peso, taken as a proxy for Trump's strength because of his tough immigration stance, fell to the weakest levels ever against the dollar.
Oil fell sharply, while safe-haven bets -- gold and 10-year U.S. government bonds -- rallied.
Markets across Asia lost as much as 5 percent of their value.
"Right now, the markets are heading for the hills, but we'll see," Robert Tipp, chief investment strategist, global bonds and foreign exchange at Prudential Fixed Income, told CNBC. "That's a function of fear as much as fact."
In recent days, markets rallied on a broad expectation Clinton would win, which was seen as a more stable outcome for investors. Any sign of Trump strength was greeted with a sell-off.
A Trump victory could also upset expectations that the Federal Reserve would raise interest rates next month. Traders had estimated the chances of a rate hike at greater than 80 percent, but Bloomberg reported that market odds dropped below 50 percent as the night went on Tuesday.