ACH Fraud Prevention Is Officially Part of the NACHA network
For years, the responsibilities surrounding ACH fraud prevention tended to fall more heavily on the originating side of the transaction.
That made sense. The ODFI and the organization originating a payment were in the best position to know whether the transaction being sent was legitimate.
But fraud has changed.
Credit-push fraud, scams, account takeover and money mule activity have demonstrated that stopping fraud at the point of origination alone isn’t enough. Fraudsters look for weaknesses throughout the payment system, including the accounts receiving fraudulent funds.
NACHA’s new ACH fraud monitoring rules recognize that reality.
As of June 2026, all RDFIs are required to establish and implement risk-based processes and procedures designed to identify ACH credit entries initiated due to fraud. NACHA describes the broader objective of its new rules as reducing successful fraud attempts and improving the industry’s ability to recover funds after fraud occurs.
In other words, fraud prevention in the ACH Network is increasingly becoming everyone’s job.
A Stronger ACH Network Requires Controls at Every Point
There is a basic principle in fraud prevention: make yourself a harder target.
If one financial institution strengthens its controls, criminals look for another institution. If one payment channel becomes harder to exploit, criminals look for another channel.
But when an entire network raises the bar, fraud becomes harder to perpetrate in the first place.
That is one of the important ideas behind NACHA’s new approach. Its risk-management framework recognizes that Originators, ODFIs, RDFIs and other participants all have roles to play in detecting, preventing and recovering from fraud involving ACH payments.
For RDFIs, that represents an important change in thinking.
Instead of simply receiving and posting incoming ACH credits, institutions should also be asking:
Does this transaction make sense?
And fortunately, answering that question doesn’t have to mean reviewing every ACH transaction manually.
Risk-Based Monitoring Should Find the Exceptions, Not Create More Work
The words “risk-based” are important.
The objective shouldn’t be to generate an alert for every large transaction, every international payment or every unusual SEC code. That approach can quickly overwhelm fraud teams with alerts that provide very little value.
The objective is to identify the relatively small number of transactions that present enough risk to warrant additional attention.
NACHA itself identifies approaches such as velocity checks, anomaly detection, behavioral tolerances and pattern recognition as possible methods for identifying fraudulently initiated credit transactions.
That philosophy closely matches how we have approached ACH monitoring within SimpliRisk.
PayLynxs has developed approximately 30 recommended ACH monitoring patterns that institutions can use as a starting point and then adjust based on their own risk profile. SimpliRisk’s monitoring recommendations include patterns involving SEC code mismatches, higher-risk SEC codes, unusual transaction volumes and frequencies, ACH WEB activity, IAT transactions and indicators of possible account takeover.
For example, our recommendations can look for circumstances such as unusually high numbers of ACH transactions over a short period, unexpected WEB activity, international ACH activity, or significant ACH activity involving a relatively new account relationship. The goal isn’t simply to find a transaction that is “large.” It is to identify activity that has characteristics associated with greater fraud risk.
That distinction matters.
Good fraud monitoring doesn’t necessarily produce more alerts. It produces better alerts.
Bringing Real-Time Monitoring to Incoming ACH Activity
To help financial institutions respond to the new requirements, PayLynxs has expanded SimpliRisk to support real-time ACH monitoring.
As ACH/NACHA transaction files are received for processing, SimpliRisk can scan the activity against the institution’s selected monitoring rules and generate fraud alerts when suspicious activity is identified.
The monitoring rules can also be categorized by the type of risk being identified—including high dollar activity, high volume or frequency, higher-risk SEC codes, SEC mismatches, sudden changes, payroll anomalies and account takeover indicators.
For a fraud team, that means the focus can remain where it belongs: investigating the activity that presents the greatest risk rather than manually reviewing routine transactions.
Automation is particularly important here. A new monitoring responsibility shouldn’t require financial institutions to build an entirely new manual process around incoming ACH files. The more that screening, risk identification and alert generation can happen automatically, the more sustainable the program becomes.
Stronger Controls Don’t Have to Mean a Bigger Budget
We also believe ACH fraud monitoring needs to be practical for institutions of every size.
For existing SimpliRisk clients, we’ve made real-time ACH monitoring available on the platform. For institutions that don’t currently use SimpliRisk, we offer a stand-alone ACH monitoring service, with pricing increasing based on transaction volume.
We made that decision deliberately.
The objective of the NACHA rule is to strengthen the ACH Network. The easier and more affordable it is for financial institutions to implement meaningful fraud controls, the stronger that network becomes.
Compliance shouldn’t require blowing up the technology budget.
More Than a Compliance Exercise
There will always be a temptation with a new rule to ask, “What is the minimum we need to do to comply?”
But this particular rule presents an opportunity to ask a better question:
“What can we see today that we couldn’t see before?”
Real-time, risk-based ACH monitoring can give financial institutions another opportunity to identify suspicious activity before funds disappear further into the financial system.
And when thousands of institutions improve those controls at the same time, the benefit extends beyond any individual bank or credit union.
It makes ACH a harder place for criminals to operate.
That’s good for individual financial institutions. It’s good for their accountholders and members. And ultimately, it’s good for the entire financial system.
That’s exactly the kind of fraud prevention we should all be working toward.
