DECEMBER 9, 2010, 10:24 AM ET
How Much is Howard Stern Worth to Sirius?

By Shira Ovide

After pulling his typical end-of-contract threats to jump ship, Howard Stern has agreed to stay with Sirius XM Radio.

Associated Press
It’s not yet clear how much Sirius had to fork over to keep Howard happy. But shareholders seem to be cheering.

Shares of Sirius XM are 6.5% higher so far this morning. That means at the stroke of Stern’s pen on a new contract, he’s helped add $315 million to Sirius’s market value.

Stern helped vault Sirius to the mainstream when he agreed to leave terrestrial radio for satellite in 2004 as part of a contract worth $500 million in cash and stock. As his original agreement drew to a close, Stern teased listeners for months about the possibility of leaving. “I don’t think I’m going to be re-signing,” he said on the air a year ago.

Speculation stirred about Stern retiring, about him joining the judging panel on “American Idol,” even signing onto some kind of deal with Apple’s iTunes. Some Sirius XM officials didn’t take his threats seriously, figuring Howard wasn’t likely to make the same level of money anywhere else.