Quote from Option Trader:
I have a hard time to believe the posts that these are all "high risk" stocks because there are stocks that have no exposure to subprime mortgages on the list like IBKR (based on their own claims), DRL, and others; also IBKR would never say about themselves to the investment world that they view themselves as "high risk". Also note that the maintenance requirement is 30%.
However, I do feel IB should re-evaluate this list to consider whether or not the individual stocks on the list really have a risk of dropping 50% overnight--else at least to give that much margining.