In 2000, the market for ACH transactions in the United States was poised for growth. By 2004, new payment types had begun to restore annual ACH volume growth to historical levels, and a surge of volume from new consumer debit applications helped lift network growth by 19.9%. As a result of new initiatives and shifts in the US payments industry as a whole, the ACH network is now being used for more purposes than ever before. This TowerGroup Research Note explores how changes have contributed to the current state of the network and are setting the stage for the next five years. It considers what has stayed the same, what's new, and whether we are seeing a transformation in the market.