VAMP (Visa Acquirer Monitoring Programme)

VAMP represents a structural simplification of Visa’s acquirer monitoring architecture. For years, acquirers and merchants had to manage compliance separately under VDMP (which tracked dispute ratios) and VFMP (which tracked fraud ratios), each with separate thresholds, remediation timelines, and fee schedules. VAMP merges these into a single metric and shifts the compliance relationship to sit primarily between Visa and the acquirer.

The Unified VAMP Ratio

The VAMP ratio is calculated as:

(Disputes + Unadjusted TC40 reports + Enumeration events) / Total transactions

Key components:

Disputes: Confirmed chargebacks initiated by cardholders, counted at the transaction level.

TC40 reports: Fraud reports filed by issuers through the Visa TC40 process when a cardholder reports fraud. These are included in VAMP whether or not they result in a formal dispute, which means a merchant can be contributing to VAMP exposure through issuer-reported fraud even when cardholders do not formally file chargebacks.

Enumeration: Card-testing attacks (high-velocity low-value authorisation attempts against a merchant’s payment endpoint) are explicitly included, reflecting Visa’s view that merchants who are being enumerated against create network-level risk.

Thresholds and Enforcement

The standard threshold is 0.9% — exceeding this initiates a monitoring period with enhanced reporting requirements. The excessive threshold is 1.8% — breaching this exposes the acquirer to fines and programme fees assessed by Visa.

The 1,000-transaction minimum means low-volume merchants are excluded from the programme, focusing enforcement on material transaction volumes.

Acquirer-Level Enforcement

Because VAMP enforcement sits at the acquirer level, acquirers are incentivised to proactively manage merchant-level ratios rather than waiting for Visa to intervene. In practice, acquirers now have contractual mechanisms (reserve requirements, merchant-level surcharges, and offboarding rights) that they deploy based on per-merchant VAMP contribution analysis — merchants do not deal with Visa directly on VAMP.