ACH Filter

An ACH filter is a fraud control offered by US banks that allows ACH debits to post to an account only if they come from originators the account holder has approved in advance. The customer gives the bank a list of permitted company IDs, often with a maximum amount or frequency for each, and the bank automatically returns any debit that does not match, usually as unauthorized. It is a more flexible version of an ACH debit block, which stops all debits. Filters suit businesses that pay some suppliers, tax authorities or lenders by ACH pull but want to stop anyone else using their account number. Many banks pair filters with ACH positive pay, which alerts the customer to unmatched debits so they can decide whether to pay or return them, and with wider fraud prevention tools.