A regular guest on Howard Stern's syndicated radio show said he will testify Feb. 23 in a probe of trading of Sirius Satellite Radio Inc. shares, which surged last fall when Stern announced he was mov

NEW YORK (AP) -- A regular guest on Howard Stern's syndicated radio show said he will testify Feb. 23 in a probe of trading of Sirius Satellite Radio Inc. shares, which surged last fall when Stern announced he was moving his program to the company.

Chaunce Hayden, who writes gossip and other celebrity news for Steppin' Out magazine, received a subpoena Feb. 17 ordering him to appear before Securities and Exchange Commission investigators in New York to discuss "trading in securities of Sirius Satellite Radio."

Hayden said Feb. 20 that an SEC attorney, who phoned him before the subpoena was issued, asked about the reactions of Stern and his staff when Stern's move to Sirius was announced in October.

Hayden told the New York Post that the SEC attorney described the probe as an investigation of insider trading. Hayden told The Associated Press on Feb. 20 that he did not remember the conversation with the attorney clearly and could not say whether that description of it was accurate.

Sirius shares soared almost 30% early on Oct. 6 when Stern announced the five-year, $500 million deal to move his program to Sirius beginning in 2006 when his contract with Infinity Broadcasting Corp. ends. The shares finished trading that day nearly 16% higher, closing at $3.87, on volume that was nearly five times the stock's normal.

Hayden said he never owned Sirius stock but had publicly predicted about two weeks before Stern's announcement that the shock jock would take his show to Sirius. He said he based that prediction on his own reporting rather than inside information.

"We've all been wracking our brains to figure out why I've been subpoenaed," Hayden said.

Spokesmen for New York-based Sirius did not return phone calls and e-mails seeking comment. An SEC spokesman declined to comment.

The satellite programming is not regulated by the Federal Communications Commission, which has increasingly battled Stern over the show's racy content.