In accordance with the rules and regulations of ACH, no financial institution may simply issue an ACH transaction (whether it be debit or credit) towards an account without prior authorization from the account holder (known as the Receiver in ACH terminology).
An ACH entry starts with a Receiver authorizing an Originator to issue ACH debit or credit to an account. An Originator can be a person or a company (such as the gas company, a local cable company, or one’s employer). Depending on the ACH transaction, the Originator must receive written (ARC, POP, PPD), verbal (TEL), or electronic (WEB) authorization from the Receiver. Written authorization constitutes a signed form giving consent on the amount, date, or even frequency of the transaction. Verbal authorization needs to be either audio recorded or the “Originator” must send a receipt of the transaction details before or on the date of the transaction. A WEB authorization must include a customer reading the terms of the agreement and typing or selecting some form of an “I agree” statement.
Once authorization is acquired, the Originator then creates an ACH entry to be given to an Originating Depository Financial Institution (ODFI), which can be any financial institution that does ACH origination. This ACH entry is then sent to an ACH Operator (usually the Fed) and is passed on to the Receiving Depository Financial Institution (RDFI), where the Receiver’s account is issued either a credit or debit, depending on the ACH transaction.
The RDFI may, however, reject the ACH transaction and return it to the ODFI with the appropriate reason, such as that there were insufficient funds in the account or that the account holder indicated that the transaction was unauthorized. An RDFI has a prescribed amount of time in which to perform returns, ranging from 2 to 60 days from the receipt of the ACH transaction. However, the majority of transactions, if going to be returned, are done so within 24 hours from midnight of the day the RDFI receives the transaction.
An ODFI receiving a return of an ACH entry may re-present the ACH entry two more times, or up to three total times, for settlement. Again, the RDFI may reject the transaction. After which, the ODFI may no longer represent the transaction via ACH.