Stronger ACH Fraud Controls Are Coming: Prepare for Nacha’s New Rules

When does the ACH fraud monitoring rule take effect?

• March 20, 2026 (for organizations that originate > 6 million ACH transactions)

• June 19, 2026 (for everyone else who processes ACH payments)

Who is affected by this rule?

The changes will affect any business that processes electronic payments, from payroll deposits to vendor payments. Specifically, the rule applies to ACH originators and receivers.

What are the anticipated benefits?

• Fraud monitoring reduces the incidence of successful fraud and improves the quality of transactions in the ACH Network.

• Expanding fraud detection duties to more parties in the ACH Network creates more chances to find and stop fraud. This is especially true for fraud that uses credit-push payments.

How will these new rules impact originators?

Many originators will need to implement or update their fraud-detection processes and procedures. This will be more of a lift for companies that are not currently monitoring fraud. Organizations that already use a monitoring system for WEB Debits or Micro-Entries will feel fewer effects.

Covered institutions will need risk-based controls that detect deception and false pretenses—not just unauthorized access. Originators should monitor behavioral anomalies, social engineering tactics and misrepresented identities.

With less than six months to prepare for Nacha's ACH fraud control rules to take effect, now is the time to:

• Check your current fraud detection systems and processes : Find gaps and have your risk team look at your ACH account validation. They should also review your real-time fraud detection abilities.

• Implement or upgrade monitoring processes to fill in the gaps : Please refer to the best practices section below.

• Educate your teams about the new Nacha requirements.

• Review your contracts : Your legal team should assess vendor and partner agreements' alignment with the new fraud monitoring requirements.

• Plan your ongoing compliance strategy : stablish regular processes to review fraud monitoring processes at least annually.

3 best practices for proactive fraud monitoring

1. Validate account information. Account validation is a critical pre-transaction step, especially for first-time use of an account number. Scrutinize all payments to a new account number or a new vendor for a designated period.

2. Employ real-time fraud detection. The most secure payment systems use behavioral analysis to distinguish legitimate customer activity from fraud. Originators must establish a baseline of normal activity to be able to detect outliers and suspicious patterns.

3. Sudden changes in payment details. Someone pretending to be a vendor or employee asks to change their bank account number. This is concerning if the request comes from a generic email address, not the official company domain.

4. Velocity spikes. Watch for a sudden, big increase in the number or amount of payments being sent. This is important, especially to a new account or one that was not used much before.

5. Unusual dollar amounts. Flag payments that fall outside the typical range for an employee's salary or a vendor's invoice amount.

6. Small-dollar test transactions followed by larger withdrawals. These may indicate credential testing.

7. Multiple ACH credits from unrelated sources deposited into a single account, followed by quick withdrawals. This behavior suggests possible mule account activity.

• Sudden changes in payment details. Someone pretending to be a vendor or employee asks to change their bank account number. This is concerning if the request comes from a generic email address, not the official company domain.

• Velocity spikes. Watch for a sudden, big increase in the number or amount of payments being sent. This is important, especially to a new account or one that was not used much before.

• Unusual dollar amounts. Flag payments that fall outside the typical range for an employee's salary or a vendor's invoice amount.

• Small-dollar test transactions followed by larger withdrawals. These may indicate credential testing.

• Multiple ACH credits from unrelated sources deposited into a single account, followed by quick withdrawals. This behavior suggests possible mule account activity.

Simplify ACH fraud monitoring with CSG Forte

CSG Forte empowers your organization to meet Nacha’s evolving ACH fraud monitoring standards with confidence. Whether you run a small business or a large company, Forte’s solutions help you meet Nacha and industry rules. This gives you peace of mind in a complicated payment world.

CSG Forte Verify uses two strong tools. CSG Validate checks account and routing numbers. CSG Authenticate confirms who owns the account.

Together, these solutions help prevent impersonation and unauthorized ACH transactions. With Forte’s advanced technology, you can lower fraud risk, improve transaction accuracy, and reduce false positives. This ensures a smooth experience for your customers.

Forte’s real-time transaction monitoring analyzes payment activity as it happens, identifies behavioral anomalies and flags suspicious transactions before anyone moves funds. This proactive approach strengthens your defenses and helps safeguard your business from evolving fraud threats.

Preparing for Nacha’s new fraud monitoring requirements doesn’t have to be overwhelming. Talk to CSG’s risk management experts . They can help you with your needs and create a plan to keep your organization safe and compliant.