Can there ever be a situation that one can get an after-hour liquidation on stocks with IB? It would seem to me this question would only be relevant to a stock which the intraday & overnight margining are the same. If this concern exists, then it would seem possible for a stock that closes at $20, and the extended hours bid is $10, for someone to hit the bid (even if it's his own in another account), and lead to the downfall of someone else's account.