Satellite rivals Sirius Satellite Radio and XM Satellite Radio split the retail sales market in the 2006 second quarter, as the boost Sirius got from the addition of Howard Stern to its lineup appears to be fading, Bridge Ratings announced June 15.

Bridge, which interviewed satellite radio buyers at retail outlets between Jan. 1 and June 12, projects that throughout the last 15 weeks the two satellite radio providers added 1.7 million subscribers combined, with XM having a 50.2 percent share and Sirius 49.8 percent. Based on the sales trend, Bridge now projects XM will end 2006 with 8.4 million subscribers, while Sirius will have 6.5 million. These projections do not take into account auto dealership sales, which accounted for about 13 percent of total subscribers in the fourth quarter of 2005 and first quarter of 2006.

Bridge estimates 1.3 million of Stern’s terrestrial fan base, or about 11 percent, has migrated to Sirius and has found “an apparent apathy regarding future Sirius subscriptions.”