Already a 17% shareholder, Bristol-Myers Squibb laid down a $4.5 billion offer to buy the rest of ImClone shares, the Wall Street Journal reports. The $60-a-share offer, sent to ImClone chairman Carl Icahn today, is a 29% premium on yesterday's closing price and makes Bristol the second pharma giant to gun for its biotech partner in as many weeks.
The news sent ImClone’s stock rocketing to a four-year high of $65.36, meaning investors believe that Bristol will have to up the ante to close a deal. ImClone stock has risen more than 40% in the past year—thanks to the good buzz surrounding its Erbitux cancer treatment—but it’s still probably best known as the stock that landed Martha Stewart in jail.