Sirius-XM Radio (SIRI) warned of slower subscriber growth and posted a third-quarter loss of more than $200 million as the newly merged company was hurt by the slumping auto industry.

In its first release since merging, Sirius-XM disclosed a pro forma net loss of $217 million, or nine cents per share, compared to a net loss of $265.5 million, or 18 cents per share, a year ago. Sirius-XM’s revenue jumped 16% to $613 million.

Analysts polled by Thomson Reuters had expected a loss of nine cents per share on revenue of $574.88 million.

“Sirius-XM third quarter results demonstrate strong revenue growth, solid cost control and most importantly a clear path to positive cash flow,” CEO Mel Karmazin said in a statement.

The results included a $4.8 billion impairment charge to goodwill, principally related to the decline in Sirius-XM’s share price since the February 2007 merger agreement.

The company also said it will delay filing its quarterly 10-Q report for up to five days to review required purchase accounting adjustments.

Sirius-XM added 344,100 subscribers in the third quarter, bringing its total to 18.9 million, up 17% from a year ago. The company said subscriber growth was hurt by the “dramatic” slowdown in auto sales.

The company predicted a return to profitability, saying it anticipates positive free cash flow of $1 billion in 2012.

“In the first 60 days following the merger, Sirius-XM is operationally very close to breakeven,” Karmazin said.

Despite the bleak auto outlook, Sirius-XM backed its 2008 and 2009 revenue outlook. The company sees its subscriber growth building to 20.6 million at the end of 2009 and eclipsing 28 million by the end of 2013.