qaz exactly thank you, I think many people who do ETF investing are not prepared for this risk as highly unlikely as it is, that's why Im curious if IB has ever done anything like this, where they just change the liquid ETF margin to 100percent/no margin
Also further imagine below that
Eg
ETF (changed) :100% margin
Mike has : actually cash value is -100k (original 100k cash - 200k margin loan)
Mike has: 200k worth of ETF (ETF value went down to 200k)
Margin call: 200k - which means Im totally wiped out!
I will let the experienced IB users answer your question. Just fyi, if your positions are liquidated at market price and the spreads are not that wide, the only "cost" is slippage (the spread and commissions incurred). Not much harm done to your account.