The selling is most likely caused by long term investors trying to avoid large capital gain tax increases that will be imposed on them next year by Obama. Many CELG longs have huge long term gains. It's better to sell now, while you know what the tax rate is. Then buy the stock back next year when the pressure is gone. Good luck.
"Merck is moving to diversify its portfolio by creating a new division, Merck BioVentures, which leverages a platform for both new biologics and so-called "follow-on" biologics -- or generic biotech medicines.
Many drugmakers are investing more into the lucrative area of biologics, which treat conditions such as cancer, multiple sclerosis and rheumatoid arthritis and are derived from living cells as opposed to synthetic chemicals." Reuters 10am today..