Sirius XM Won't Be Caught in Big Three Pileup

"Regardless of whether you're the federal government or you oversee the bankruptcy proceeding, you are interested in maintaining this cash inflow," says Ratcliffe. "Sirius XM is a net contributor to the automakers. It's not a supply contract. It's more of a customer relationship. This is not the sort of contract that would get restructured in a bankruptcy."

Of course, the revenue share economics for Sirius XM varies a little bit with each automaker, with the older agreements being less beneficial to Sirius XM than the newer ones. Ratcliffe says that GM is one of the older relationships and that the revenue share Sirius XM pays to GM is notably higher than the revenue share to everybody else. "On the margin, the larger the portion of the U.S. vehicle fleet that is non-GM, the lower the costs are," Ratcliffe says.

Ratcliffe takes it a step further, though, arguing that in the near term it would be a benefit to Sirius XM's cash flow if there were fewer autos sold in the U.S. "If fewer cars are being sold, that's less money being spent acquiring new customers," he says. "Down the line, that reduces the number of radios in cars. But in the near term, you're spending less money upfront, which improves their cash flow position."

While the idea of selling less satellite radios sounds awful for Sirius XM's prospects, Ratcliffe may be right. In the company's third-quarter earnings report released earlier this month, Sirius XM said its cost per gross subscriber addition was $74, an improvement of 15% over the year-ago cost per gross subscriber addition of $87. Essentially, a lower auto sales number means that $74 figure could come down even further -- meaning Sirius XM would spend less cash.