The VAMP ratio is one of the most important payment-risk metrics that all merchants should understand in 2026. This ratio allows Visa, acquirers, and processors to understand whether a merchant has excessive fraud and dispute activity.
VAMP stands for Visa Acquirer Monitoring Program. This is Visa’s program for monitoring for fraud and disputes in merchants, replacing the Visa Dispute Monitoring Program and the Visa Fraud Monitoring Program. The VAMP ratio is calculated by dividing the number of fraud and dispute reports for Visa transactions by the total number of settled Visa transactions.
Why Businesses Need to Understand Visa VAMP Rules
Visa accepts that fraud and chargebacks are two separate issues to monitor. However, merchants will find that their fraud and non-fraud chargebacks are part of the same Visa VAMP ratio. Therefore, merchants that experience an increase in fraud and chargebacks will suffer the most from VAMP ratios.
High-risk merchants that sell ecommerce, subscription, SaaS, digital goods, travel, adult, dating, gaming, CBD, vape, nutraceutical and card-not-present products may be greatly impacted by the VAMP ratio. These merchant categories are exposed to friendly fraud, which will affect their VAMP ratio calculations.
Friendly fraud can significantly impact the VAMP ratio. According to Visa Acceptance Solutions’ 2026 Global eCommerce Payments & Fraud Report, 64% of merchants are seeing an increase in friendly fraud. This means merchants are seeing more instances where customers place an order and authorize it with the merchant’s Visa account, but then dispute the transaction.
Who Should Monitor the VAMP Ratio
This guide is most useful for merchants who are:
- high-risk merchants
- ecommerce businesses
- subscription and continuity merchants
- SaaS and digital goods companies
- CBD, vape and nutraceutical sellers
- adult, dating and gaming merchants
- travel and ticketing businesses
- merchants with rising chargebacks
- merchants receiving warnings from their payment processor about their enumeration ratio
Any business that relies on online transactions and payments benefits from monitoring the VAMP ratio. However, businesses that depend on digital products or services, or have a high volume of online transactions, may benefit more from monitoring this ratio. If your business receives a warning from your payment processor regarding your enumeration ratio, your VAMP ratio is likely already problematic.
VAMP Ratio vs Enumeration Ratio
The standard VAMP ratio and the VAMP enumeration ratio measure different risks. One looks at fraud and disputes after transactions settle. The other looks at authorization activity that appears to be card testing.
| Metric | Formula | Plain-English Meaning | Why It Matters |
|---|---|---|---|
| VAMP Ratio | Fraud reports + disputes ÷ settled Visa transactions | Measures fraud and disputes compared with Visa sales volume | Shows whether the merchant has too much combined fraud and dispute activity |
| TC40 | Included in numerator | Visa’s fraud report record | Fraud reports can affect VAMP even before the merchant thinks of the issue as a chargeback |
| TC15 | Included in numerator | Visa’s dispute or chargeback record | Customer disputes are part of the VAMP risk picture |
| TC05 | Used as denominator | Settled Visa transaction count | Gives the ratio its transaction-volume base |
| Enumeration Ratio | Enumerated authorization attempts ÷ total authorization attempts | Measures suspected bot-driven card testing | Identifies checkout abuse before or during fraud attempts |
| VAAI | Used to flag likely enumeration | Visa Account Attack Intelligence | Helps Visa identify likely account-testing behavior |
For merchants, the practical point is simple: VAMP is not just about chargebacks. It also includes fraud reports and separately monitors enumeration attacks, which are bot-driven card-testing attempts on a checkout page.
VAMP Ratio Calculation Examples for Merchants
The easiest way to understand the VAMP ratio is to calculate it with simple examples.
| Fraud Reports | Disputes | Settled Visa Transactions | VAMP Ratio |
|---|---|---|---|
| 10 | 15 | 10,000 | 0.25% |
| 25 | 50 | 10,000 | 0.75% |
| 50 | 100 | 10,000 | 1.50% |
| 100 | 150 | 10,000 | 2.50% |
The same number of disputes can create different pressure depending on transaction volume. A merchant with 150 combined fraud and dispute events across 10,000 settled Visa transactions has a very different ratio from a merchant with 150 events across 100,000 settled transactions.
That is why Payment Nerds recommends looking at VAMP performance by source rather than just total volume. Merchants should review disputes and fraud by product, subscription plan, sales channel, location, affiliate, ad campaign, checkout page, refund reason and billing model.
VAMP Monitoring Tools and Support Compared
Reducing the VAMP ratio usually requires a mix of monitoring, prevention and response tools. No single tool fixes every source of fraud and disputes.
| Tool or Support Type | Best Fit | Key Strength | Main Tradeoff |
|---|---|---|---|
| Payment Nerds | Merchants that need VAMP-aware payment strategy and account stability | Helps with ratio monitoring, high-risk underwriting, Verifi, Ethoca, 3DS, fraud controls and processor-fit guidance | More consultative than a standalone software tool |
| Verifi | Merchants that need Visa-focused pre-dispute tools | Helps resolve disputes before they become formal chargebacks | Needs clear refund rules and configuration |
| Ethoca Alerts | Merchants that want early issuer fraud and dispute alerts | Gives faster notice so merchants can refund, stop fulfillment, or investigate | Does not replace root-cause prevention |
| 3DS | Higher-risk card-not-present transactions | Adds issuer authentication to reduce fraud exposure | Poor setup can add checkout friction |
| Fraud Filters and Velocity Rules | Ecommerce and subscription merchants | Helps block suspicious behavior before approval or fulfillment | Needs tuning to avoid false declines |
| Bot and Enumeration Controls | Merchants with failed-authorization spikes or checkout abuse | Helps stop card-testing traffic before it scales | Requires ongoing monitoring |
These tools work best when they are connected to the merchant’s payment workflow. A merchant that adds Verifi but keeps confusing subscription terms may still create disputes. A merchant that adds fraud filters but ignores checkout bots may still face enumeration pressure.
What VAMP Ratio Calculations Mean for High-Risk Merchants
High-risk merchants should treat the VAMP ratio as an operating metric for their business. It is not just a compliance metric. The VAMP metric can highlight problems in fraud, disputes, billing, fulfillment, refunds, checkout, or customer experience.
The acquirer’s pressure is also part of the VAMP metric. This metric monitors the merchants and the acquirers. If the merchant engages in high-risk activities, the acquirer also has reason to intervene. This could mean implementing remediation plans, increasing reserves, increasing processing limits, providing new tools to the merchant, or terminating the merchant’s account with the acquiring bank.
Payment Nerds can help high-risk merchants understand what is driving their VAMP ratio. Some of the factors affecting the VAMP ratio for merchants include fraud, subscription cancellations, affiliate traffic, refund times, fulfillment times, descriptor issues, and card-testing issues. Each of these problems has a fix associated with it.
How to Lower Your VAMP Ratio
First, merchants must measure the fraud reports and disputes that occur within their stores. Keep an eye on TC40 fraud reports, TC15 disputes, refund returns, failed authorizations and the reasons for chargebacks and complaints against customers.
Then, fix the following:
- Use clear billing descriptors
- Refine the refund and cancellation process
- Send renewal and billing reminders
- Add Verifi and Ethoca alerts
- Use 3DS for high-risk transactions
- Improve fraud filters
- Monitor failed authorizations
- Block bots on the checkout page
- Review disputes by product line
- Review and address processor concerns before they become escalated
It’s not enough to fight chargebacks and disputes. It’s more important to reduce the instances that enter into the VAMP ratio altogether.
VAMP Ratio Monitoring and Compliance Costs Explained
The cost of VAMP ratio monitoring will depend on your merchant risk, transaction and dispute volume, and your payment stack. Monitoring tools can factor in chargebacks, Verifi, Ethoca, 3DS, fraud screening, bot protection software, and staffing costs.
The real question is, what does your unmanaged VAMP ratio cost? High VAMP ratios can cost merchants in fees, reserves, reviews, workload, revenue, and terminated accounts. High-risk merchants will usually find it cheaper to monitor VAMP ratios proactively than to remediate the damage done when the payment processor gets involved.
Payment Nerds can show merchants what payment tools are worth the cost of implementation. A lower-risk merchant does not require the same payment tools as a high-risk merchant, such as a continuity subscription merchant, travel business, adult platform, or CBD ecommerce store.
Common VAMP Ratio Mistakes to Avoid
The biggest mistake is treating the VAMP ratio as if it were an old chargeback ratio. Because the VAMP ratio considers both fraud reports and chargebacks, a merchant that does not track chargebacks will miss half the ratio.
Another mistake is to ignore authorization attempts. The enumeration ratio considers both approved and declined authorizations. It is possible to have authorization abuse without any orders ever being attempted.
Finally, another mistake is ignoring that the ratio will appear in the Above Standard or Excessive category. Because the VAMP ratio combines fraud reports with chargebacks, the merchant will have to catch fraud and chargeback issues before they become visible to the VAMP ratio.
Key Components of the VAMP Ratio Calculation
Understanding TC40 Fraud Reports
TC40 is Visa’s fraud report record. In plain English, this is the way that Visa keeps records of the fraud activity that is reported to its system. Fraud reports are not limited to chargebacks; these reports are part of the VAMP ratio. A merchant can reduce the number of fraud reports associated with the TC40 record by improving fraud screening processes such as AVS and CVV checks and 3DS processes, or by reviewing orders for potential fraud activity prior to fraud reports being recorded in the system.
Understanding TC15 Disputes
The count represented by TC15 is the number of Visa disputes that the merchant receives. These can be related to fraud activity, friendly fraud activity, product dissatisfaction, the need for a refund, subscription issues, billing issues, delivery issues, or customers who call the bank to initiate a refund instead of the merchant. These dispute counts are combined with the fraud report counts (TC40) in the VAMP ratio. Thus, fraud and dispute management needs to be combined into a single department or team to monitor the VAMP ratio with accuracy and efficiency.
Understanding TC05 Settled Transactions
This count is the number of settled Visa transactions. This forms the denominator in the VAMP ratio. Settled transactions are the Visa transactions that the merchant processes. Thus, volume counts for merchants with high VAMP ratios. A merchant that processes a small number of settled Visa transactions can easily have a high VAMP ratio.
How the VAMP Ratio Formula Works
The VAMP ratio formula is: VAMP Ratio = Count of Fraud Reports (TC40) + Count of Disputes (TC15) ÷ Count of Settled Visa Transactions (TC05) Using the example that the merchant has 40 fraud reports, 60 disputes, and 10,000 settled Visa transactions, the VAMP ratio calculation would appear as: (40 + 60) ÷ 10,000 = 1% This 1% figure is the one that the merchant, the processor, or the merchant’s acquiring bank will compare to the VAMP ratio rules related to Visa cards.
How the Enumeration Ratio Formula Works
The enumeration ratio is separate from the VAMP ratio. Enumeration ratios relate to enumeration attacks on a merchant’s website. Enumeration attacks use bots to automatically test stolen or guessed credit card information. These failed attempts may go unnoticed by the merchant if only completed orders are reviewed. However, the enumeration ratio monitors these failed attempts, as well. The enumeration ratio is determined by dividing the number of enumerated authorization transactions by the total number of authorization transactions. This total includes both approved and declined transactions.
Understanding VAMP Above Standard and Excessive Tiers
The Above Standard and Excessive VAMP ratio levels are the thresholds that will trigger fees and scrutiny from Visa for merchants with too high of a VAMP ratio. The fact sheet that Visa publishes includes the thresholds for the acquiring bank’s merchants and the thresholds for merchants in the excessive VAMP ratio category. For the AP, Canada, EU, and United States regions, the excessive merchant threshold is 220 basis points (bps) for the VAMP ratio, reducing to 150 bps beginning April 1, 2026. However, merchants should confirm this threshold with their acquiring bank or payment processor. Factors that can influence the VAMP ratio threshold for merchants include the region in which they operate, the date in which the merchant is assessed for the ratio, and the business model of that merchant.
FAQs About the VAMP Ratio
Q: What is the VAMP ratio?
A: The VAMP ratio is the number of fraud reports plus the number of non-fraud disputes divided by the number of settled Visa transactions. It measures the amount of fraud and disputes that a merchant encounters compared to their sales.
Q: What are Visa VAMP rules?
A: Visa VAMP rules are the regulations regarding the monitoring of merchants and acquiring companies for instances of fraud, disputes, and enumeration activity. Companies that register high VAMP ratios are at the risk of receiving fees from Visa.
Q: What are TC40 and TC15 records?
A: TC40 is the Visa fraud report record. TC15 is the Visa dispute or chargeback record. These two records are used to calculate a company’s VAMP ratio.
Q: What is the enumeration ratio?
A: The enumeration ratio is the number of enumerated authorizations divided by the total number of authorizations. This number helps Visa determine if there are any bot attacks using test credit cards on a merchant’s checkout page.
Q: What is an enumeration attack?
A: An enumeration attack is an attack by bots that tests test credit cards on a merchant’s checkout page. These types of attacks can cause spikes in failed authorization attempts for a merchant.
Q: What is VAAI?
A: VAAI stands for Visa Account Attack Intelligence. This score helps Visa identify any instances of enumeration or test card activity for transactions that do not require presenting a credit card.
Q: How can Payment Nerds help with VAMP ratios?
A: Payment Nerds can review a merchant’s VAMP ratio and provide recommendations regarding the use of Verifi, Ethoca, 3DS, fraud prevention software, bot protection and a strategy to maintain their current transaction volumes.
Conclusion
The VAMP ratio is derived by dividing the number of fraud reports and Visa disputes by the number of settled Visa transactions. The enumeration ratio is calculated separately as the number of suspected card-testing transactions divided by the total number of attempted transactions.
If your business is looking for help with understanding the rules of Visa’s VAMP ratio, how to lower your VAMP ratio, and how to manage your enumeration ratio, Payment Nerds may be of some assistance to your business. It’s not about the ratio itself. It’s about maintaining a healthy account – before it becomes a processor problem.
Sources
- Visa. “Visa Acquirer Monitoring Program Fact Sheet.” Accessed May 2026.
- Visa. “Visa Account Attack Intelligence Score.” Accessed May 2026.
- Visa Acceptance Solutions. “2026 Global eCommerce Payments & Fraud Report.” Accessed May 2026.
- Merchant Risk Council. “Stricter VAMP Ratio Thresholds Are Now in Effect.” Accessed May 2026.
- Verifi. “Resolve Pre-Disputes Automatically.” Accessed May 2026.
- Ethoca. “Ethoca Alerts.” Accessed May 2026.
- Stripe. “3D Secure 101.” Accessed May 2026.
- PCI Security Standards Council. “Merchant Resources.” Accessed May 2026.
