How is this very low margin interest rate possible?

[ET180]

Margin is ONLY charged interest if it is kept over night past 11:59:59 PM. If it's not kept but only used for 23 hours and 59 minutes and 59 seconds you pay ZERO interest. This may be different from broker to broker as to when they administer the interest but more or less that is what it is.

Sorry for bringing back an old thread, but isn't interest only charged if you have a negative cash balance? Cash balance is the amount of excess cash you hold in your account. It is one component of your Net Liq which is the total account value. Margin is a risk metric. At IB, it will only directly cost you if IB decides to assess a "Net Exposure Fee" which seems arbitrary and they basically are saying that you are taking on too much risk. Is that correct?