Biotech slides, broader markets even

The BioCentury 100 Index lost 166.21 points, or 2.8%, to 5,714.16 on Thursday, while the broader markets remained relatively flat. The BC100 is a price-weighted index of top U.S.-listed biotechs by market cap. The day's big decliners included Gilead Sciences Inc. (NASDAQ:GILD), which fell $2.95 (4%) to $79.92 on the day, and Celgene Corp. (NASDAQ:CELG), which closed off $6.63 (4%) to $156.61.

Other healthcare indices also fell on Thursday. The NYSE Arca Biotechnology fell 2.5% and the NASDAQ Biotechnology fell 2.6%. The NYSE Arca Pharmaceutical Index slid only 0.4%. There was no obvious news catalyst for the sell-off. In a note on Thursday's slide, ISI's Mark Schoenebaum said a massive sell-off in biotech is "unlikely" but said a "more modest correction is, in theory possible, since all the stocks now trade above conservative [discounted cash flow] analyses." ...