U.S. stocks take another tumble; eBay heads lower

NEW YORK - U.S. stocks are heading lower after a mixed batch of corporate earnings reports. Biogen Idec, Gilead Sciences and other biotech companies extended their recent slump.

The Standard & Poor's 500 index fell 27 points, or 1.45 percent, to 1,845 as of 1 p.m. ET Thursday. The Dow Jones industrial average lost 166 points, or 1 percent, to fall to 16,270. The Nasdaq composite index dropped 89 points, or 2.46 percent percent, to 3,511.

EBay dropped 3 percent on news that Carl Icahn is backing down from his campaign to shake up the company.

Biotechnology companies fell sharply. The sector has become volatile in recent weeks amid scrutiny over the cost of their drugs.