Skip Navigation: Internet Banking Login. An overdraft can happen when you write a check, withdraw money from an ATM, use your debit card to make a purchase, or make an automatic bill payment or other electronic payment for more than the available funds in your checking account. A transaction that brings your account into a negative balance is called an overdraft. A transaction that would bring your account negative but the bank returns unpaid is called non sufficient funds or insufficient funds transaction. Banks may charge a fee for either an overdraft or a returned unpaid transaction. Each bank is different as it applies to the fees charged, and these fees may vary depending on the amount of the negative balance, or even the number of overdraft or nonsufficient funds transactions you have had previously. Also, recipients of non-paid items can also charge you fees of their own, independent of any bank fees you may owe. If you do not address overdraft fees or fail to correct the situat...