> or they closed a particular stock at their whim This happens all the time, a ticker will get halted for a time and no one can trade them even though the mark

> or they closed a particular stock at their whim This happens all the time, a ticker will get halted for a time and no one can trade them even though the market is open. http://www.nasdaqtrader.com/Trader.aspx?id=TradeHalts http://www.nasdaqtrader.com/Trader.aspx?id=TradeHalts