From my understanding IB offers intraday margin of 25%, as in if you $25,000 you can buy up $100,000 worth of equities. However, when I was doing margin checks, the maintenance margin and initial margin appear to be the same. So, if you max out your margin at 4x, you will be liquidated with a small move against you. Is that correct? Seems like a pointless feature to have if that is true since your initial margin must be much lower leverage than 4x for any realistic trading.
They will do a margin call if you go in the red a few percentage points. This is how it works on retail and institutional trading.
The margin call at IB will not be after you "go into the red by a few percent". They update your account balances every few minutes. If your available margin is less than 5% of your account balance you'll get a warning message. But if your available margin goes negative, you'll here "ding" indicating that liquidation(s) have occurred. No additional warning, no delays, nada.