Last summer, Mel Karmazin was rattling off his trademark one-liners to talk up the future of Sirius XM Radio, the combined company he ran that had just been blessed by regulators.

He was planning to cut costs and expand a business that was already a fixture in the lives of millions of Americans. “Forty-three cents a day — it’s not even vending machine coffee,” he said at the time, parrying a question about whether the softening economy might hurt subscriptions.

But now Sirius XM, the satellite radio company, has problems with much bigger price tags. It has hired advisers to prepare for a possible bankruptcy filing, people involved in the process said.

That would, of course, be a grim turn of events for the normally upbeat Mr. Karmazin, Sirius XM’s chief executive, who had hoped to create a mobile entertainment juggernaut with stars like Howard Stern.

It is unclear how a bankruptcy would affect customers. Service is unlikely to be interrupted, but the company might have to terminate contracts with high-priced talent like Mr. Stern or Martha Stewart.