The three-letter system that lets banks exchange electronic payment instructions in the United States is ACH.
ACH stands for Automated Clearing House, a network for processing electronic credit and debit transfers. Direct deposits, recurring bill payments, tax payments, and many business-to-business transfers can use ACH processing.
Unlike a card network, ACH generally moves funds between bank accounts using bank-account and routing information. Transactions are commonly processed in batches rather than individually in real time, although same-day ACH services are available.
ACH is often confused with a wire transfer. Wire transfers are typically designed for direct, high-value or time-sensitive movement of funds, while ACH is widely used for recurring and mass electronic payments.