Editing ACH Network (section)

=== Next-day ACH===
ACH debits and credits are transactions that are created, batched, and transmitted to an ACH operator, typically by way of a financial institution's connection to the ACH Network.

With next-day ACH, each ACH transaction is cleared overnight. The sending institution (called the Originating Depository Financial Institution) sends the transaction to the receiving institution (called the Receiving Depository Financial Institution). When the receiving institution receives the transaction, it has until the end of the next working day to send a rejection to the sending institution. If the sending institution does not receive a return from the receiving institution by the morning of the third business day, then the transaction is deemed to be successful.

Waiting for a timeout for two business days is an antiquated feature of ACH that lingers on from the 1960s when the ACH system was designed and implemented. It is not as quick as real-time payment networks. Consequently, ACH debit or credit transactions can take four working days to complete.