The S&P 500 fell 61 points, or 2.4 percent, to 2,445.
Although historically considered a strong month for markets, this December has proved dismal for benchmark indexes. Without a decent rally, this could be the worst December since 1931.
Out of the 11 major S&P 500 sectors, only the Technology and the Industrials are staying in the negative territory.
After steady gains through the spring and summer, stocks have nosedived in the fall as investors worry that global economic growth is cooling off and that the US could slip into a recession in the next few years.
Investors are responding to a weakening outlook for the US economy by selling stocks and buying ultra-safe USA government bonds. Markets tend to move, however, on what investors anticipate will happen well into the future, so it's not uncommon for stocks to sink even when the economy is humming along.
Political chaos from Brexit, a looming US government shutdown and the resignation of US Defense Secretary James Mattis are stoking fear, too.
The Nasdaq is the first of the three major USA stock indexes to cross that threshold, with its drop in less than four months the latest sign that the bull market that began during the financial crisis a decade ago could be nearly done. And rising interest rates in the USA could slow its economy even more.
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The second argument is that Weinstein's accusers are lying about the nature of their sexual contact with the movie mogul. In May, Harvey Weinstein turned himself in to police following allegations by several women of sexual misconduct.
Williams' comments come after the Fed said on Wednesday it would largely stick to its plan to keep raising interest rates, spooking investors already grappling with mounting evidence of slowing growth and triggering the slide on Wall Street.
Scott Wren, senior global equity strategist at Wells Fargo Investment Institute, said investors felt Fed Chairman Jerome Powell came off as unconcerned about the state of the USA economy, despite deepening worries on Wall Street that growth could slow even more in 2019 and 2020.
"Nasdaq is your more growth-oriented story, so the biggest stocks are driving the overall market because they're a bigger chunk of it", said Kim Forrest, senior portfolio manager at Fort Pitt Capital Group in Pittsburgh.
The S&P 500 index surrendered 50.80 points, or 2.1 per cent, to 2,416.62. The Dow fell 464.06 points, or 2 percent, to 22,859.60 after sinking as much as 679 during the day.
The Dow was down 1,655 points or 6.9 percent for the week, the largest weekly loss since October 2008.
Major U.S. indexes are now 16 to 26 percent below the peaks they reached in the summer and early fall.
Oil prices continued to retreat.
On Friday the price of USA crude slipped 0.6 percent to $45.59 a barrel in NY.
Bond prices rose. The yield on the 10-year Treasury note fell to 2.78 percent.