Since April 2025, acquirers have been on a new journey with Visa’s updated Visa Acquirer Monitoring Program (VAMP). But this shift doesn’t just affect acquirers; payment service providers (PSPs) and independent sales organizations (ISOs) may also feel the impact of these changes—especially those operating in the card-not-present (CNP) and recurring payment (RP) spaces.
VAMP’s enhanced monitoring and compliance requirements mean that all players in the payments ecosystem will need to take proactive steps to manage fraud and dispute rates, ensuring they align with Visa’s updated standards.
This isn’t just another routine shift or fine-tuning of Visa regulations—it’s a consolidation and enhancement of the previous Visa Fraud Monitoring Program (VFMP) and Visa Dispute Monitoring Program (VDMP) into a single, rigorous compliance framework focused on aggressively managing medium and high-risk merchants.
As outlined in our previous post, “How Did We Get Here? A History of Monitoring Programs,” VAMP marks a significant advancement, requiring acquirers to strengthen fraud prevention measures, enhance merchant support, and improve reporting precision. With VAMP enforcement under way, the time to act is now.
Below, we outline five of the primary challenges for acquirers under VAMP:
1. Building Stronger Communication with Merchants and ISOs
The top challenge for acquirers under the updated Visa Acquirer Monitoring Program (VAMP) is establishing effective communication with merchants and ISOs. For successful compliance, merchants and ISOs must clearly understand the new thresholds and expectations to plan and implement necessary operational changes. Without proactive communication, acquirers risk the costly prospect of needing to eliminate non-compliant merchants from their portfolios or facing significant fees, which could hurt profitability and damage the acquirer’s reputation.
If you haven’t already, now is the time to discuss these changes with your merchants and ISOs, as VAMP introduced a major shift in compliance dynamics by moving the focus from fraud dollars to fraud units. This change, detailed in our previous post, “What We Know About VAMP,” could disproportionately impact smaller merchants who previously maintained compliance by staying within dollar limits but may now struggle with unit-based metrics. This shift makes close collaboration among acquirers, ISOs, and merchants more essential than ever.
The technical demands of compliance can be overwhelming for many merchants and ISOs, making acquirer support indispensable. Successfully meeting VAMP’s new compliance requirements calls for something of a relationship reset between you and your merchants, pivoting from the compliance sticks of reserve increases and merchant eliminations to focusing on creative and cooperative problem solving:
- Educating Merchants and ISOs on VAMP Requirements: Setting clear expectations and communicating specific compliance thresholds helps merchants and ISOs make timely operational adjustments. Providing this information early can reduce attrition and reinforce the acquirer’s role as a supportive partner. Hosting webinars or publishing compliance updates, as recommended in “How to Prepare Merchants for VAMP,” helps ensure merchants understand their responsibilities under the new VAMP framework.
- Balancing Support and Enforcement: Striking the right balance between guidance and enforcement is crucial, especially for high-risk merchants. Providing early support can prevent compliance issues later, fostering stronger, longer lasting relationships and increased monthly recurring revenue (“MRR”).
This collaborative approach empowers all parties to navigate VAMP’s complexities successfully. To support acquirers in this transition, Slyce360 offers a merchant handbook for VAMP you can share with your merchants to help them meet the new requirements.
2. Achieving Accuracy in VAMP Ratio Reporting
The second challenge is achieving accurate VAMP ratio reporting, a crucial requirement for compliance with Visa’s standards, particularly as acquirers calculate their own VAMP ratios. As we pointed out in our previous post, “What We Know About VAMP,” the updated ratio calculation requires acquirers to subtract resolved disputes—such as Rapid Dispute Resolutions (RDRs), Chargeback Dispute Resolution Network (CDRN) cases, and confirmed Compelling Evidence 3.0 cases—from the total TC40 fraud units. To handle this data-intensive process, acquirers may need to consider:
Creating a Unified System for Data Matching: To accurately calculate VAMP ratios, acquirers must link TC40 data with resolved disputes, including RDRs, CDRNs, and CE 3.0 cases, on a transaction-by-transaction basis. This process can be complex, as it requires comprehensive access to merchant mitigation data, which has not always been readily available. For instance, CDRN data has traditionally been stored outside of Visa Resolve Online (VROL), limiting direct access for acquirers.
To achieve a complete and accurate view of a merchant’s VAMP ratio, acquirers may need to collaborate closely with Visa or coordinate with their merchants to obtain necessary data. Integrating detailed metadata within sales and refund authorization payloads can further improve data alignment and matching, ensuring more precise VAMP calculations.
Embracing the Use of Acquirer Reference Numbers (ARNs): ARNs are critical for matching TC40 and dispute mitigation data accurately. If an acquirer has not yet implemented ARNs in its systems, now is the time to prioritize this change. Using ARNs provides a reliable method to link TC40 reports and dispute resolutions, making VAMP calculations more precise and reducing compliance risks.
3. Managing Enumeration Ratio
The third challenge is managing the enumeration ratio, a compliance metric under VAMP that tracks the frequency of “enumeration attacks,” where fraudsters attempt to validate card details by testing various combinations of card numbers, expiration dates, and other data. Managing the enumeration ratio poses distinct challenges for acquirers, particularly when dealing with medium and high-risk merchants and ISOs, whose comparatively aggressive reauthorization strategies may be mistaken for enumerations attacks.
- Enumeration Ratio Adds Complexity: Calculating the Enumeration Ratio will be even trickier because its numerator is determined by Visa’s Account Attack Intelligence (VAAI) tool.
- Enhanced Data Monitoring and Analysis: The enumeration ratio requires acquirers to track not only successful transactions but also failed authorization attempts that may signal fraud attempts. Acquirers will need sophisticated monitoring tools capable of identifying patterns that indicate enumeration activities.
- Stronger Fraud Detection Tools: To manage enumeration risk, acquirers must deploy advanced fraud detection tools, such as AI-driven systems or machine learning algorithms, to detect and respond to suspicious patterns in real time. These tools will help differentiate between legitimate customer/merchant actions and potentially fraudulent activity.
- Educating Merchants: Merchants and ISOs may not be aware of the enumeration risks they face, especially those in high-risk industries such as digital goods or recurring billing. Acquirers will need to educate merchants on the best practices, such as implementing CAPTCHA, rate-limiting, multi-factor authentication, or modified reauthorization strategies, to minimize unauthorized or “empty calorie” attempts and keep enumeration ratios within acceptable levels.
- Balancing Security with Customer Experience: While stringent security measures can help reduce enumeration ratios, they may also disrupt the authorization of legitimate transactions and create friction for customers. Acquirers will need to strike a balance to maintain security without negatively impacting the consumer experience.
- Continuous Monitoring and Compliance Risks: Enumeration attacks often occur in sudden spikes, which requires continuous monitoring. Failure to manage these attacks could lead to enumeration ratio thresholds being exceeded, resulting in compliance penalties. Investing in 24/7 monitoring systems and responding quickly to unusual activity will be essential for meeting VAMP standards.
By addressing these challenges with proactive measures, acquirers can better manage the impact of the enumeration ratio, protect merchant and ISO relationships, and strengthen compliance under VAMP.
4. Preparing for the OneERS Acquirer Risk Tool
The fourth challenge for acquirers is understanding the role of OneERS, Visa’s risk management tool under the updated VAMP program. The tool is expected to play a central role in acquirers’ compliance and risk monitoring, but there are concerns about its reliability and how far acquirers can depend on it. Here’s what to know about OneERS and its limitations:
- Centralized Risk Reporting: OneERS is designed as a real-time, consolidated platform for tracking critical compliance metrics like fraud units, disputes, and enumeration attempts. New systems like OneERS often require time to become fully accurate and reliable, so acquirers should validate its figures rather than rely on them alone.
- Real-Time Alerts and Proactive Monitoring: The tool is intended to alert acquirers when a merchant’s metrics approach threshold limits, allowing them to address risks proactively. New alert mechanisms need time to fine-tune and minimize false positives, so acquirers relying on existing, possibly outdated systems, or on OneERS alone, may still struggle to prioritize and respond to emerging risks.
- Advanced Fraud Detection with Visa’s Account Attack Intelligence (VAAI): OneERS is designed to integrate VAAI to help identify enumeration attacks and account abuse, which would be a valuable addition.
- Operational Efficiencies with Microsoft Dynamics Interface: Designed to run on a Microsoft Dynamics interface accessible via Visa Online, OneERS is expected to offer self-service and automated case management features.
- Compatibility Challenges with Existing Systems: Leveraging OneERS fully may require acquirers to have compatible, updated systems. Those relying on legacy technology could face additional costs and delays in upgrading. Furthermore, acquirers currently lack clarity on how well their existing systems will integrate with OneERS, adding another layer of uncertainty to the implementation process.
- Potential Issues with Merchant Communication and Education: Acquirers need an effective way to communicate compliance data to merchants, especially those who may already be non-compliant under the new thresholds. Without it, merchants can be left unprepared for VAMP standards, raising the risk of compliance issues. Inconsistencies and the usual adjustment period for new systems may limit how much clear guidance OneERS gives merchants and ISOs, which underscores the need for acquirers to have other ways to communicate compliance expectations.
- Complications with Reporting for Audits and Reviews: OneERS is designed to streamline audit reporting, but like any new system it may need a period of adjustment to ensure reporting accuracy and consistency across audits and regulatory reviews.
5. Assessing VAMP’s Impact on Overall Business Strategy
The final challenge acquirers face is the overall uncertainty surrounding how the updated VAMP program is impacting their business. Many acquirers still don’t have the tools they need to manage VAMP effectively. This lack of resources leaves them navigating complex requirements without clear insights into how VAMP affects their operations, merchant relationships, MRRs and profitability.
This uncertainty also complicates the process of underwriting new business, particularly in medium and high-risk categories. Without reliable tools and data to assess risk accurately, acquirers may find it challenging to make informed underwriting decisions in these more profitable segments of the payments ecosystem.
To mitigate some of this risk, acquirers may increasingly and proactively require merchants to participate in Visa’s Rapid Dispute Resolution (RDR) and Chargeback Dispute Resolution Network (CDRN) programs. While these programs can help manage disputes and reduce chargebacks, they add significant costs that take a big bite out of a merchant’s bottom line. Striking a balance between compliance and affordability will be essential to ensure that merchants can continue to thrive without being weighed down by the added financial burden of these compliance tools.
This is Where Slyce360 Comes In
Don’t let VAMP shorten your merchants’ lifespan. More than just a compliance monitoring tool, Slyce360 is a comprehensive platform designed to help acquirers, ISOs, and merchants actively meet evolving compliance thresholds including VAMP with advanced analytical tools that identify growing fraud, dispute, and operational concerns. With customized alerts, acquirers, ISOs, and merchants can monitor and manage emerging trends, ensuring that VAMP requirements don’t limit their long-term potential. Equipped with real-time data, intuitive reporting, and powerful collaboration tools, Slyce360 empowers all stakeholders to stay ahead of compliance requirements efficiently and proactively.
Slyce360 also features Dispute Mitigation Optimization tools that maximize the effectiveness of RDR and CDRN investments, allowing merchants to target areas for optimizing dispute mitigation strategies and boosting their bottom lines. This creates a win-win: merchants save money while meeting mitigation requirements, and acquirers and ISOs manage compliance costs more effectively for their merchants. Slyce360’s collaborative platform fosters seamless cooperation among acquirers, ISOs, and merchants, aligning them toward shared compliance goals and offering a competitive edge in today’s constantly evolving regulatory landscape.
There’s truly nothing like it on the market—let us show you how Slyce360 can work for you, keeping your merchants compliant, confident, and ready to thrive.