Why Exelixis Stock Trounced the Market on Thursday

Cancer drug specialist Exelixis (EXEL 5.02%) was quite the stock market star on Friday. Following news that it's making a big, shareholder-pleasing move, market players piled into the company to push its shares 5% higher on the day. This provided some light in what was generally a gloomy trading session, with the S&P 500 index falling by 1.7%.A $500 million moveAfter market close on Thursday, Exelixis announced that it will launch a new share repurchase program, authorized for up to$500 million worth of it ...