Sirius Satellite Radio ( SIRI) said Wednesday that it intends to issue 75 million common shares in a public offering, sending the company's stock sharply lower in Nasdaq trading. Shares of the satellite radio broadcaster fell 26 cents, or 11%, to $2.09 on the news. Last Friday, Sirius jumped after the company was upgraded by two analyst firms , lending to a month-long rally that had doubled its share price. The stock offering's pricing is subject to market conditions. Sirius expects the offering to be underwritten by Morgan Stanley and UBS Warburg, the company said in a press release. Separately, the company said the Blackstone Group's affiliates are considering transferring to their partners a maximum of 57 million shares of Sirius stock. The shares consist of 6.3% of Sirius' outstanding common stock. Affiliates of Blackstone also hold warrants to purchase about 42 million Sirius common shares with an average exercise price of about 99 cents each.