When there is not enough money in your account, we decline all ATM withdrawals and one-time recurrent debit card transactions.
Some transactions may still go through even if you do not have enough money in your account and may result in overdrawing your account. Examples include checks you write, or card transactions in which the merchant authorizes your card for a fixed amount that may differ from the final amount you pay, such as a gas pump purchase or a restaurant bill with a tip.
It is important that you monitor your spending and your available balance to avoid overdrawing your account.
Here is what to do should you have a negative balance https://bankmobile.custhelp.com/app/answers/detail/a_id/2737