Who has the cheapest margin fees/cost among TD Ameritrade, Tiger Broker and interactive broker (MARGIN), not cash account?

User of TD here. TD does not charge fees on margin. but if there is over leverage (maybe due to fat finger or share price crash etc), there will be margin call. as far as I remembered, it took about 1 week to top up my account. by then, you could have missed the dateline and they could already have force close your positions.

not sure about the others. hope it helps.​​​