Banks sometimes encode items with a special transaction code to ensure payments are received before other items clear an account. The codes are used for a variety of reasons. As long as you make a deposit or have enough money in your account to cover the transaction, you don't have to take further action.
A "force pay" debit is a special transaction code used by banks to insure that a debit purchase clears an account first. If pending transactions in the amounts of $4.75, $299.02, $65.91, $29.99 and 79 cents have not cleared your account and a force pay item for $100.00 appears, the bank will clear the $100.00 before clearing any of the already pending transactions.
A bank may be more likely to use the code when a third party cashes a check that is drawn on the bank. For example, if a business pays an independent contractor with a payroll check and the contractor cashes the check instead of depositing it into an account at the bank, the bank may document the check as a force pay item to ensure the funds are recouped as quickly as possible.
If a bank pays for an item that you do not have enough money in your account to cover, the item may appear as a force pay debit on your checking account statement. This is done so the bank can recoup the money as quickly as possible. Once you make a deposit, the bank will cover the cost of the paid item and any charges that occurred as a result of the overdraft.
Federal Reserve Overdraft Law
According to the Federal Reserve Overdraft Law, unless you opt in to participate in an overdraft protection program, banks are prohibited from paying for an item for which you do not have enough money in your account to cover. If you have opted in participate in such a program, the bank may clear the transaction and mark it as a force pay item.