The Dow Jones industrial average dropped 318 points, nearly 2 percent, to close at 15,879 Friday, its worst drop since last June.
The Dow is down almost 500 points over the past two days as investors pull out of stocks and emerging markets and stash money in safer assets like bonds.
The Standard & Poor's 500 index fell 38 points, or 2.1 percent, to 1,790. The Nasdaq composite fell 90 points, or 2.2 percent, to 4,128.
Small-company stocks fell even more than the rest of the market as investors shunned risk. The Russell 2000 plunged 28 points, or 2.4 percent, to 1,144.
Bond prices rose. The yield on the 10-year Treasury note fell to 2.73 percent.
