XM and GM today announced that GM plans to build more than 1.8 million cars with factory installed XM receivers.

On a day when Sirius is down 6% to $3.91 and almost touched its 52-week low and XM is down 3% to $14.16, both on news that SIRI will miss year-end subscriber targets, a little good news is welcome.

What XM did not say, and what Wall St. would like to know, is whether the GM installation will have any effect on XMSR subscription growth for next year.

But, they aren’t talking.

Douglas A. McIntyre can be reached at douglasamcintyre@247wallst.com. He does not own securities in companies that he writes about.