Suppose somebody was close to maxed out with their margin, and today's price drop pushed them over the 2:1 edge. Say, around 3:30pm. I know that brokerage firms officially have the right to begin indiscriminately liquidating portfolios, with or without advance warning or time to do a wire transfer... but I suspect that most brokerages won't actually DO it without warning unless something UTTERLY dire happens. I'm not asking because I'm in danger... I'm asking because I'm planning tomorrow's shopping trip and trying to get some idea of when the suicidally-cheap deals are likely to start showing up. Or, possibly, is THAT the reason why the market REALLY nosedived HARD around 3:30, and stocks like Microsoft and LDK almost instantly dropped a buck within a matter of seconds?