Closing Bell: Crude Closes at 12-Year Low; U.S. Stocks End Mixed

U.S. stocks made a surprise turn higher in the final hour of the session after an unpredictable day of trading. Benchmark indexes had been under pressure after another sharp drop on Chinese markets. Crude oil plummeted again to close under $32 a barrel for the first time in 12 years. West Texas Intermediate lost just over 5 percent to settle at its lowest level since December 2003. Celgene (CELG) shares tumbled after the biotech reported preliminary full-year results that missed forecasts. Profit estimates were reduced to reflect dilution from its August acquisition of Receptos. Under Armour (UA) sank after Morgan Stanley analysts downgraded shares to UNDERWEIGHT. The firm said it had grown bearish on the fitness apparel brand as average selling prices decline and it loses markets share. TheStreet's Keris Lahiff reports from Wall Street.