Dow futures - a bet, before trading opens, on where stocks would go - had plunged 550 points Friday morning, triggering a temporary trading halt.
"This is beyond volatile. It is chaotic," Carl Weinberg, chief economist at High Frequency Economics wrote in a morning note to clients. "This is the kind of day when the central banks step into the market with an
'unexpected' interest rate move to calm things down."
Instead, it was just another day's loss, one in a series since mid-September that have erased nearly $7 trillion in value from stocks.
Before U.S. markets opened, CNBC flashed a rundown on the level of losses that would trigger trading circuit-breakers, which close the market after steep losses. The first circuit-breaker, a 90-minute halt, would kick in if the Dow lost 1,100 points before 2 p.m.
The Dow fell more than 500 points in the morning, but steadied itself, even though the only good news was the 5.5 percent increase in September existing home sales. That was tempered by median home prices, which dropped to $191,600, down 9 percent from a year ago.
The Dow closed at 8,378, its lowest finish since 8,306 on April 25, 2003. In the last six weeks, the Dow has experienced triple-digit moves in 27 of 30 trading sessions.
Broader indexes also fell more than 3 percent.
The paper loss for the week on the broadest stock index, the Dow Jones Wilshire 5,000, was $800 billion. A sell-off Wednesday, coupled with the losses Tuesday and Friday, gave the index its eighth-worst week since 1979. The index closed at its lowest level since May 2003.
Total losses in the Dow Jones Wilshire 5,000 since the market's Oct. 9, 2007, high are $8.8 trillion, or 44 percent.
Stock investors avoided panic even as oil fell sharply, closing near $64 a barrel, despite a decision by the OPEC cartel to cut production quotas by 1.5 million barrels a day. OPEC officials, meeting in Vienna, left no doubt that they were ready to slice production again quickly if Friday's decision does not end the price freefall.
"Oil prices have witnessed a dramatic collapse - unprecedented in speed and magnitude," the 13-nation cartel said in a statement.
The dollar plunged below 93 yen, a 13-year low. The British pound fell 8 cents against the dollar, its largest intraday drop since 1971.