Nine in ten American workers are paid through it. Ninety-nine percent of Social Security payments move through it. Popular apps like Venmo, PayPal, Cash App, and Zelle quietly depend on it behind the scenes. Yet most Americans have never heard of it.
A new paper by A. Joseph Warburton, Professor of Law at the Syracuse University College of Law and Professor of Finance at the Whitman School of Management, is the first comprehensive academic study of that network: the Automated Clearing House, or ACH. Published in the Summer 2026 issue of The Business Lawyer, the peer-reviewed journal of the American Bar Association’s Business Law Section, “Moving Money and Undoing It: The Architecture of ACH” explains how the system moves money for direct deposits, bill payments, and business-to-business transfers, and what happens when something goes wrong.
ACH payments now exceed checks, credit cards, and debit cards in total dollar value, and growth is accelerating: the value of ACH transfers grew more than twice as fast from 2018 to 2021 as it did in the prior three-year period. Despite that scale, Warburton’s article notes that the network has largely escaped academic study in part because it operates behind more visible payment brands and lacks the marketing budgets of card networks like Visa and Mastercard.
The paper’s central finding involves what happens after a payment goes through. Unlike newer “instant” payment systems such as RTP and FedNow, wire transfers, or cryptocurrency, ACH allows a sender to reverse a payment for up to five banking days after it has settled and potentially even if the recipient has spent the money. Warburton argues that this built-in error-correction feature, unique among major payment rails, may help explain why ACH has remained dominant even as faster alternatives have entered the market.
As Warburton writes in the article, “In payments, mistakes sometimes happen. ACH offers a host of methods for undoing payment. Under the right circumstances, ACH payments can be stopped after they’ve been initiated and even reversed after they’ve hit the recipient’s account, potentially after the recipient has spent the money. Undoing payment is easier and more powerful on the ACH network than on other electronic payment rails, a unique balance of speed and error resolution that can help the ACH network remain ascendant in the face of payment competition.”
The article also examines how ACH is governed: primarily through the operating rules of Nacha, a nonprofit association of financial institutions, supplemented by federal consumer-protection law such as Regulation E and, for non-consumer transfers, Article 4A of the Uniform Commercial Code.