(CNBC) U.S. stocks closed mixed Friday as biotech stocks plunged and investors digested Nike earnings.
The Nasdaq composite closed down 1 percent after falling more than 1.5 percent in afternoon trade, pressured by decline of nearly 5 percent in the iShares Nasdaq Biotechnology ETF (IBB).
IBB had its worst day since April 2014, falling in record trade volume to below its closing low from the Aug. 24 "flash crash." The index closed in bear market territory, or more than 20 percent below its 52-week high. Forty-five percent of the Nasdaq 100 also closed in bear market territory.
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