Nacha Rule Change Mandates Broader ACH Fraud Screening for Banks

A significant update to the Nacha Operating Rules that took full effect over the past year is compelling banks to expand their fraud detection systems across a much wider range of electronic payments. The new risk management framework, which became effective in phases through 2023, now requires originating depository financial institutions (ODFIs) to implement a “commercially reasonable fraudulent transaction detection system” for all Automated Clearing House (ACH) payments, a major shift from previous rules that focused more narrowly on internet-initiated debits.

This rule change directly targets the escalating problem of credit-push fraud, where legitimate account holders are deceived into sending payments to accounts controlled by criminals. These schemes, most notably Business Email Compromise (BEC), have resulted in billions of dollars in losses for U.S. companies. In a typical BEC scam, a fraudster impersonates a senior executive or a known vendor and sends an email directing an employee to make an urgent ACH payment to a new or updated bank account.

Because the payment is initiated by an authorized user at the victim company, traditional fraud detection methods that look for unauthorized access were often ineffective. The payment itself is technically authorized, even though it is based on fraudulent pretenses. Nacha’s updated rules aim to close this gap by placing a greater responsibility on the financial institution that originates the payment to monitor for signs of fraud before the funds are sent.

Under the new framework, the requirement for a commercially reasonable fraud detection system now applies to all ACH transactions, including common business payments like vendor invoices, payroll direct deposits, and B2B transfers. Previously, this mandate was largely limited to WEB debits, or payments initiated online by consumers. By extending the rule, Nacha is pushing the banking industry to adopt more sophisticated monitoring for the types of transactions most frequently exploited in credit-push fraud schemes.

Nacha has intentionally not prescribed specific technologies or systems, allowing banks flexibility in what they deem “commercially reasonable.” This generally involves systems that screen payments against risk factors such as new or unusual payment destinations, payment amounts that deviate from historical patterns, transactions initiated from unrecognized IP addresses, and other behavioral anomalies. The goal is to flag potentially fraudulent payments for further review before they are executed, rather than trying to claw back funds after the fact, which is notoriously difficult with ACH transfers.

For financial institutions, compliance with the expanded rule has required significant operational and technological investment. Banks have had to upgrade or replace legacy monitoring systems to handle the increased scope of transactions. This includes ensuring their systems can effectively analyze B2B payment flows, which often have different characteristics than consumer payments. The change also increases the operational workload for fraud investigation teams, who must now analyze a larger pool of flagged transactions, balancing the need for security with the risk of creating friction for legitimate customers.

Small and mid-sized businesses, which are frequent targets of BEC scams, are the ultimate intended beneficiaries of this heightened security. However, they are also likely to experience the direct consequences of its implementation. As their banks roll out more sensitive fraud detection, businesses may find their own legitimate payments being delayed or temporarily blocked for review. A company making a payment to a new vendor or an existing vendor with updated banking information might trigger an alert, requiring manual verification and delaying the transaction.

Business owners may also face new security protocols from their banks when initiating payments, such as additional authentication steps or callbacks to verify high-value or unusual transfers. While these measures provide an important layer of protection, they can also disrupt established workflows, particularly for time-sensitive payments like payroll or critical supply chain invoices. Companies will need to adapt their internal processes to account for the possibility of these new bank-side reviews and potential delays.

In our experience, while these enhanced bank-level controls are a welcome safeguard, they can also introduce unexpected delays and administrative burdens for companies not prepared for them. We've seen clients' crucial vendor payments or payroll runs get flagged by new, opaque bank algorithms, causing friction with suppliers and employees. This is where proactive financial risk management becomes critical. Businesses cannot afford to be passive and rely solely on their bank's systems for protection. They must implement their own robust internal controls, such as strict multi-person approval workflows for all payments, out-of-band verification for any changes to vendor payment information, and regular audits of payment templates and beneficiary lists.

These internal defenses are a core component of the financial risk management strategies we design for clients at C&S Finance Group LLC. Building a resilient payment process that satisfies new banking protocols while minimizing business disruption is essential in this evolving landscape. To understand how to adapt your company’s payment operations to this heightened security environment, contact C&S Finance Group LLC at csfinancegroup.com for a consultation.

As banks continue to fine-tune their systems to comply with the Nacha rules, industry experts will be watching to see how effectively the changes mitigate credit-push fraud losses. Future regulatory efforts may focus on promoting greater information sharing between financial institutions to identify and stop fraudulent actors more quickly. For now, businesses should prepare for a new normal of increased scrutiny over their electronic payments and work closely with their banking partners to navigate the changes.