This, of course, would have a huge effect on the bank balance, as you can see on the graph.
Notice that currently QBO shows zero as the threshold. The threshold is the number that the business owner really doesn't want to drop below.
Of course, no one wants to drop below zero, but it's also good business practice to have a "buffer" in your account. Dropping below this number would indicate that you need to put in effort quickly to turn things around.