NEW YORK: Shareholders in Sirius Satellite Radio and XM Satellite Radio on Tuesday approved, as expected, the sale of the latter to the former - a deal agreed in February between their respective boards. But it is by no means a done deal.

Many observers expect there to be regulatory opposition from the Department of Justice and the Federal Communications Commission.

Sirius chairman Mel Karmazin (he who refused to bend the knee to Viacom autocrat Sumner M Redstone during his stormy tenure as president/coo of the media conglomerate) proclaimed optimism about the outcome, saying he expected the deal to be legally signed and sealed by the year end.

But analysts have expressed doubt that the sale will be approved, believing the merged satellite radio companies would be deemed a monopoly. To date, however, neither of the key regulators has publicly expressed an opinion.

All now hinges on how the FCC and DoJ define the market in which the two companies are the sole operators.

If they classify it as part of the radio industry at large (as the duo insist it is), then the light is likely to be green; if they deem it to be within the narrower confines of the satellite radio market, the glow will be redder than a stop-light.

Data sourced from Wall Street Journal Online. additional content by WARC staff