XM Satellite Radio Holdings Inc. declared a regular quarterly dividend on its 8.25 percent Series B Convertible Redeemable Preferred Stock. The dividend is payable in shares of the company’s Class A Common Stock at a rate of $1.0313 per share of Series B Preferred Stock owned, with fractional shares to be paid in cash. The shares of Class A Common Stock issued will be valued at 95 percent of the average daily closing price of the stock for the 10 trading days ending July 15. The dividend is payable Aug. 1 to Series B stockholders of record as of July 22.