Originally Posted by Agent 488

Automated Clearing House (ACH) is an electronic network for financial transactions in the United States.

http://en.wikipedia.org/wiki/Automated_Clearing_House

the Federal Reserve Banks are collectively the nation's largest automated clearinghouse operator and in 2005 processed 60% of commercial interbank ACH transactions. The Electronic Payments Network (EPN), the only private sector ACH operator in the U.S., processed the remaining 40%.