New York - US stocks made their second dramatic comeback after a stunning fall this week on Thursday, the Dow adding 417 points for a 3.9% gain after losing 520 points on Wednesday.
The S&P 500 rebounded 4.57% while the Nasdaq gained 4.69% in another day of extreme volatility in markets around the world.
It was the US markets' second recovery this week, after Tuesday's jump to overcome a big loss on Monday.
"This isn't a volatile equity market. It is an extremely volatile equity market," said Patrick O'Hare of Briefing.com.
"The massive swings are symptomatic of a market that is racked with uncertainty and where every rumour is treated as truth until the real truth can set one free from the rumour. The cycle soon begins anew, though, when the next rumour hits the wires."