Understanding Visa's New Dispute Rules

On April 1, 2025, Visa introduced a new compliance framework called the Visa Acquirer Monitoring Program (VAMP). In this article, we’ll walk you through what VAMP is, what has changed, and what you need to do to stay compliant and avoid penalties.

The Visa Acquirer Monitoring Program (VAMP) is Visa’s updated program for monitoring merchants and payment processors for excessive chargebacks, fraud, and enumeration activity (i.e., fraudulent card testing attacks) on online (card-not-present) transactions done with Visa-issued cards.

This new program combines the previous Visa Dispute Monitoring Program (VDMP) and Visa Fraud Monitoring Program (VFMP) and introduces stricter rules that affect both acquirers, processors, and merchants.

For merchants in Nigeria, Ghana, Kenya, South Africa, and Côte d'Ivoire (CEMEA region), Visa flags a merchant as Excessive when its VAMP ratio is 2.2% or higher in a month, it has at least 150 fraud reports and disputes that are worth at least USD 75,000. All three of these conditions must be met.

Visa also monitors an acquirer's whole portfolio. An acquirer is seen as Above Standard at a VAMP ratio of 0.5% or higher and Excessive at 0.7% or higher. When an acquirer is above these levels, Visa can also identify the merchants that contribute most to its ratio, even if those merchants are below the merchant threshold.

The VAMP ratio combines fraud and disputes into one number. Fraud reports now count toward it even when the cardholder never files a dispute, which was not the case under the old programs.

The formula below shows how to calculate your ratio under VAMP:

{Visa fraud reports + Visa disputes} / {Settled card-not-present Visa transactions} * 100%.

Where,

• Fraud reports: This is fraud the cardholder's bank reports to Visa directly.

• Disputes: These are official chargebacks the cardholder's bank raises.

• Settled transactions: These are only completed online (card-not-present) Visa transactions in the same month. Declined attempts and in-person card payments are not included.

For example, you settle 10,000 online Visa transactions in one month. Issuers report 60 of them as fraud and raise 40 disputes. Your VAMP ratio is (60 + 40) ÷ 10,000 = 1.0%.

Visa now includes fraud reports in dispute monitoring. This is a big change, as previously, chargebacks and fraud reports were handled separately. Under VAMP, both will count toward your ratio.

That means if someone raises a fraud report against your business that doesn't get raised as a formal chargeback, it still impacts your overall dispute ratio.

Visa flags a merchant for enumeration when, in one month, 20% or more of its authorisation attempts are card testing and there are 300,000 or more of those card-testing attempts. Both of these conditions must be met.

Enumeration (card testing) is when fraudsters use scripts to try many card numbers, expiry dates or CVVs until one is approved. Visa identifies which attempts are enumeration using its own detection models.

Enumeration ratio formula:

{Enumerated authorization attempts (approved + declined) / Total number of authorization attempts (approved + declined)} * 100%.

It is important to note that:

• Not every decline counts as an enumerated attempt. Ordinary declines, such as insufficient funds or an expired card, are not enumeration unless Visa identifies them as part of an attack.

• Approved attempts can count towards your ratio. A card-testing attempt that gets approved can still count as enumeration.

For example, if in one month your business receives 2,000,000 authorisation attempts, and Visa identifies 450,000 of them as card testing; your enumeration ratio is 450,000 ÷ 2,000,000 = 22.5%. Because the ratio is above 20% and the count is above 300,000, you would be flagged.

From October 1, 2025, businesses that exceed the allowed thresholds may be subject to $4 - $8 per fraud report or dispute.

Please note that these fees will be passed to your position, so it’s in everyone’s best interest to stay compliant.

We’re working proactively to support you during this transition period. Here are some best practices for you:

1. Monitor your dispute volumes: This is the most important step. You should monitor your dispute volumes (both chargebacks and fraud claims) very closely to ensure that you’re not crossing the acceptable dispute ratio. For guidance on how to calculate your ratios, please refer to this article. At Paystack, we proactively monitor your dispute ratio using a stricter internal ratio to help you stay well below Visa’s limits, reducing the risk of warnings and fines.

2. Resolve customer issues early: Many disputes are preventable. Offer responsive customer support and proactively issue refunds when they’re due, to avoid unnecessary chargebacks.

3. Use clear billing descriptors: Confusing or vague billing names can cause customers to dispute legitimate transactions. Ensure your business name is easily recognizable on customer bank statements.

4. Keep an eye out for suspicious transaction attempts: Monitor your transaction activity for unusual or suspicious patterns that could indicate fraud, such as repeated failed attempts from the same customer, customers using weird-looking email addresses, or the same customer attempting several payments with different cards.

5. Provide thorough documentation for disputes: Always respond quickly with:

   • Proof of delivery or service fulfilment on a document that clearly shows your business name

   • Transaction records

   • Clear refund and cancellation policies that are presented to customers before payment

We’ve also put together industry-specific dispute guides to help you manage disputes more effectively.

The VAMP changes affect all of us — merchants, processors, and acquirers alike. At Paystack, we’re committed to helping you stay compliant and protect your business from chargebacks, fraud, and enumeration threats.

If you notice any suspicious transaction attempts from your customers or you have any questions at all, please don’t hesitate to reach out to our support team - support@paystack.com. Let’s work together to keep your business compliant.

• https://corporate.visa.com/en/sites/visa-perspectives/security-trust/introducing-visa-acquirer-monitoring-program.html

• https://www.chargebackstop.com/blog/visa-acquirer-monitoring-program

• https://usa.visa.com/dam/VCOM/download/about-visa/visa-rules-public.pdf

• https://www.rapyd.net/blog/visa-vamp-program/

• How to calculate chargeback and fraud ratios

• Chargeback and Fraud Monitoring Programs

• Industry-specific Dispute Guides