Visa has introduced the Visa Acquirer Monitoring Program (VAMP), which modifies the calculation and penalties related to chargeback ratios and card testing, potentially increasing penalties for card-not-present transactions. This program, effective from April 2025 and fully enforced by October 2025, supersedes previous monitoring programs and imposes stricter thresholds for both merchants and acquirers, with differentiated ratios for disputes and chargebacks. The program emphasizes the importance of fraud prevention techniques, such as Compelling Evidence 3.0, device intelligence, and Rapid Dispute Resolution, to manage and reduce chargeback ratios. Merchants face fines if they exceed new thresholds, with specific penalties applied for high-volume card testing, also known as enumeration. Regional variations exist, with different percentage allowances and transaction volume thresholds, while certain high-risk merchant categories lose previous exemptions and are now subject to the same limits as others. Using advanced tools like device fingerprinting and bot detection can help merchants lower their chargeback ratios, avoid additional fees, and better manage disputes.