VISA Acquirer Monitoring Program (VAMP)

How VAMP Ratio is Calculated 

Reported fraudulent transactions + Total disputes 
_____________________ ÷ ____________________
Total settled transactions 

Additional Details 

Only card-absent transactions are included when calculating VAMP Ratio. The number of reported fraudulent transactions is based on TC40 data. Because most of these transactions will also result in disputes, they will effectively be counted twice. Disputes that are resolved through Rapid Dispute Resolution are excluded from the dispute count, but TC40 reports for these transactions will still count toward VAMP ratio. Visa's Compelling Evidence 3.0 system can prevent both the dispute and the TC40 report from counting against the ratio. Preventing disputes through Order Insight or alerts will often avoid a TC40 report being filed, but this is at the issuer's discretion. VAMP ratio is calculated monthly based on Central Processing Date. Merchants with fewer than 1,500 applicable fraudulent or disputed transactions are excluded. 

VAMP Enumeration Ratio 

VAMP also includes a separate ratio for enumerated transactions, also known as card testing fraud. This ratio is calculated by the number of confirmed enumerated transactions divided by total settled transactions. Enumerated transactions are confirmed by the Visa Account Attack Intelligence (VAAI) system, which Visa claims reduces false positives by 85%. Merchants with fewer than 300,000 enumerated transactions are excluded. 

VAMP Thresholds

Visa announced two sets of thresholds for acquirers and merchants, the first of which went into effect when enforcement for the Excessive level began on October 1, 2025. A second, stricter set of thresholds for the Above Standard level was imposed on acquirers beginning January 1, 2026. For merchants, the ratio for the Excessive level will decrease on April 1, 2026.

VAMP Fees 

Acquirers and merchants identified as being “Above Standard” or “Excessive” under the new VAMP framework may be subject to enforcement fees. For first-time offenders within a rolling 12-month period, Visa will grant a three-month grace period during which enforcement actions will not be applied. After this grace period, however, fees may be enforced for each dispute: 

• Acquirers – Above Standard: $4 per fraudulent or disputed transaction 

• Acquirers – Excessive: $8 per fraudulent or disputed transaction 

• Merchants – Excessive: $8 per fraudulent or disputed transaction 

VAMP’s Impact on Merchants 

At first glance, it might seem like merchants have it easy with regard to the newer thresholds they need to comply with:

However, VAMP ratio effectively double-counts fraud-related disputes, and counts TC40 reports for transactions that were too small for the issuing bank to bother with a chargeback. This means most merchants see much higher ratios under the VAMP formula.

In addition, the drop from 1% to 0.5% for acquirers is a huge change, and one that may affect merchants as well. In order to comply with this new threshold, some acquirers may impose limits on their merchants’ chargeback ratios that are even stricter than Visa’s. For example, an acquirer might set a VAMP ratio threshold of 1% for its merchants in an attempt to ensure that the average across its portfolio remains below the 0.5% required by Visa. 

Acquirers are responsible for the overall performance of their portfolios, meaning that any merchant whose VAMP ratio exceeds acceptable levels could potentially jeopardize the acquirer’s compliance with VAMP. Some acquirers may levy fines against merchants with a VAMP ratio exceeding their stricter limits or even terminate merchant accounts. 

Merchants will need to be mindful of these changes and adjust their fraud prevention and dispute management practices accordingly to avoid falling afoul of the acquirer-imposed limits, even if they remain under Visa’s 1.5% threshold. It may be worth considering tools like Smart Prevention Alerts and Order Intelligence that can divert potential chargebacks, reducing the merchant’s VAMP Ratio.  

To help your company prepare for VAMP by finding ways to prevent chargebacks, speak to one of our industry experts.