XM Satellite Radio has reduced its year-end forecast from 8.5 million subscribers to between 7.7 million and 8.2 million.

The company blamed the reduction on marketplace dynamics and regulatory uncertainties, according to MediaWeek (via MediaBuyerPlanner). XM originally predicted 9 million subscribers by the end of the year, but reduced that forecast in May to 8.5 million.

XM made the announcement in conjunction with its second-quarter earnings report, and said it would refine the range at the end of the third quarter once it has a better sense of "regulatory process and availability of product for the fourth quarter," XM said in a statement. The company announced at the same time that it has surpassed 7 million subscribers.

A recent study from Targetbase, a unit of Omnicom Group, showed that consumers seem to be confused by exactly what satellite radio is and what it offers.

XM named Nate Davis, a member of its board, to the newly created position of president and COO earlier this week.