Hughes Electronics (GMH) , a unit of General Motors (GM) - Get Report, was down 13.9% in midafternoon. After the close Monday, the company warned that it expects the net gain of subscribers to its DirecTV will be about 175,000 in the second quarter, sharply below an earlier prediction of an increase of 275,000 to 350,000.

The company also lowered its full-year subscriber forecast and sharply cut its projected gain in Latin America.