You assume markets provide infinite liquidity at all times. They don't. Any broker with too many traders making gigantic unhedged short put bets puts their entire existence at risk in the event of a rapid, gigantic gap down.
In what way does IB's intraday margin requirement (which at times has been one of the highest in the active trader arena) have ANYTHING to do with exchange minimum overnight margin which would be in force?
Exchange minimum margin is a requirement for overnight trading, and it is the same for all futures brokers. So, unless you are saying IB charges more than exchange minimum margin for overnight trades, your IB-evangelist spin has been exposed as worthless.
