
System hacked warning alert on a laptop showcasing the dangers of fraud
Credit: Adaptiv Payments
Why Visa Introduced the VAMP Program
Visa introduced VAMP in 2024 to better combat fraud and enumeration attacks as digital commerce continues to expand. With more online transactions come higher (and more sophisticated) fraud, more disputes, and less stable payment behavior, especially in high-volume and cross-border industries.
Earlier monitoring programs focused on chargebacks, which appear after serious problems are already well underway. VAMP takes a broader view, examining fraud patterns, dispute activity, and merchant behavior so risk can be identified and adequately addressed earlier.
VAMP also reinforces accountability. Because Visa doesn’t work directly with most merchants, it relies on acquiring banks and processors to properly underwrite and manage the businesses they support. The program ensures acquirers stay actively involved in monitoring risk, not just reacting once issues escalate.
And while that scrutiny can feel frustrating, VAMP isn’t meant to punish legitimate businesses. It’s meant to surface risk sooner and get ahead of suspicious activity, all before small issues turn into account freezes, processing interruptions, or even bigger problems down the road.
Bottom line: Visa wants acquiring banks and processors to take chargebacks and payment card fraud much more seriously.
Key Visa VAMP Requirements for High-Risk Merchants
Visa’s Acquirer Monitoring Program evaluates merchant risk using defined ratios and behavioral indicators that signal instability within the payments ecosystem.
While Visa formally monitors acquiring banks, these measurements are driven by merchant-level transaction data.
For high-risk merchants, understanding these ratios is essential to maintaining VAMP compliance:
VAMP Ratio
The VAMP ratio is a core metric used to assess overall risk tied to a merchant’s payment activity, specifically involving both domestic and cross-border card-not-present transactions. It evaluates the relationship between these two values over a defined monitoring period:
- Confirmed fraud reports and non-fraud disputes
- Total transaction volume
A rising VAMP ratio indicates that a merchant’s transactions are producing an unacceptable level of fraud relative to their transaction volume. This can stem from weak fraud controls, high-risk customer acquisition channels, insufficient authentication, or poor transaction filtering.
The numbers: While Visa initially rolled out a 1.5% “excessive” threshold at the program’s debut, merchants now face even tighter fraud and dispute restrictions. As of January 2026, VAMP mandates that businesses keep their monthly combined dispute ratios below 0.9% to avoid fines, heftier chargeback fees, and even termination of Visa processing privileges.
How To Calculate Your Monthly Visa VAMP Ratio
Total # of Fraudulent CNP Transactions (TC40) + Total # of Disputed CNP Transactions (TC15)
Total # of Settled CNP Transactions (TC05)
The tricky part? One bad transaction can count as two strikes. If a payment is flagged as fraud and later disputed, it gets logged twice under VAMP. Think of it like one missed payment triggering both a late fee and a ding on your credit score.
Enumeration Ratio
VAMP also holds acquirers accountable when merchants fail to stop large-scale “enumeration” attacks, a type of fraud where criminals rapidly submit thousands of card attempts to test stolen card numbers and confirm which ones are active.
If a merchant allows this activity to spiral, Visa will impose fines or other enforcement actions on the acquirer. Here’s what that looks like by the numbers:
- Exceeding 300,000 suspected enumeration attempts in a month (both approved + declined)
- Having more than 20% of authorization requests tied to fraud
The good news is that most enumeration attacks are preventable. Simple safeguards like CAPTCHA tests, caps on payment attempts, and authorization controls can stop these attacks before they become a serious problem.
How To Calculate Your Monthly Enumeration Ratio
Total # of Enumerated Authorization Transactions (Approved + Declined)
Total # of Authorization Transactions (Approved + Declined)
Additional Risk Indicators
Beyond these two important ratios, Visa also evaluates:
- Unauthorized fraud reporting trends
- Dispute behavior and resolution patterns
- Sudden spikes or changes in transaction volume or speed
- Refund and reversal activity
- Billing descriptor clarity and consistency
These indicators are assessed in context, taking into account the merchant’s industry, business model, and historical behavior.
For high-risk merchants, VAMP compliance depends on proactively controlling fraud and enumeration risk rather than reacting after the above ratios deteriorate.






