This excerpt taken from the GM 10-Q filed May 8, 2009.
If the U.S. Treasury Debt Conversion occurs, any future sales of our common stock by the U.S. Treasury could adversely affect the market for our common stock.
We cannot assure you as to if, when, how or to whom the U.S. Treasury may transfer any of our common stock that it would receive if the U.S. Treasury Debt Conversion occurs (or the warrants held by the U.S. Treasury are exercised), or the effect, if any, that future sales (whether public or private) by the U.S. Treasury of our common stock would have on the market price of such stock. Sales or other transfers of substantial amounts of our common stock, or the perception that such sales could occur, could adversely affect the market price of our common stock. If the U.S. Treasury sells or transfers shares of our common stock (or the warrant) as a block, another person or entity could become a controlling shareholder of our company.