Sirius ( SIRI) dropped 9% after missing fourth-quarter estimates and trimming 2005 revenue guidance. For its fourth quarter ended Dec. 31, the New York-based pay radio shop lost $262 million, or 21 cents a share, compared with the year-ago $148 million, or 14 cents a share. Revenue jumped to $25 million from $5 million a year ago. Those numbers missed the Wall Street analyst consensus estimate, which called for a 16-cent-a-share loss on revenue of $28 million. The company also guided toward 2005 revenue of $210 million, which is below the $213 million Thomson First Call estimate. But Sirius said it was adding subscribers faster than expected and rolled out a host of ambitious subscriber-addition targets. The user gains come as the company seeks to keep pace with its older and larger, if less media-savvy, rival, Washington-based XM Satellite ( XMSR). Sirius said it added 480,969 subscribers in the fourth quarter, giving it 1.14 million users at year-end. Previously, the company had targeted 1 million subscribers by year-end. Sirius also boosted its 2005 year-end user goal to 2.5 million from 2.3 million, saying it expects subscriber acquisition costs and churn to drop. The report offers an interesting test of investor sentiment on Sirius, whose shares rocketed last year as the company signed up high-priced talent like Howard Stern and former Viacom exec Mel Karmazin. Fans say the company is on the verge of tapping a huge and lucrative mass market, but skeptics wonder how Sirius will fund its massive and ongoing losses in years ahead. Early Wednesday, Sirius fell 54 cents to $5.70.