The Dow closed 318 points lower on Friday, the biggest one-day drop since June.
As NBC News puts it, the index joined the rout that hit European and Asian markets on fears that the global economy is slowing.
"'There's a lack of buyers supporting the market and incremental sellers who are de-risking on the back of the macro developments,' said Doug Crofton, head of U.S. cash equity trading at Bank of America Merrill Lynch. 'I don't think the market was positioned for the recent events, so we are seeing downside hedges being put on.'
"'We're not seeing people throw in the towel,' or selling indiscriminately in a rush to get out of the market, he added.
"Concerns about China's economy, global central-bank stimulus and U.S. corporate earnings led to selling in risky assets this past week. The degree of volatility in global stocks, bonds and currencies caught some investors wrong-footed.
"'We're seeing funds thinking, 'there's clearly some macro risk I hadn't considered," said Ian Winer, director of equity trading at Los Angeles brokerage Wedbush Securities. 'You'll sell stocks to bring down your overall exposure, so you'll protect yourself to play another day. We're seeing funds do that.'"
"The Standard & Poor's 500 index tumbled back below the key 1,800 level, as it fell 38 points, or 2.1%, to 1,790. The S&P posted a 2.6% weekly loss.
"And the tech-laden Nasdaq composite index was off 91 points, 2.2%, to 4,128."