Velocity checks allow merchants to set velocity thresholds on various customer attributes, controlling how often a customer can attempt transactions. These checks are intended to identify high-speed fraud attacks.
To best utilize these checks merchants need to understand the behavior of their shoppers. Because the average number of transactions by a good user (e.g. once a day, twice a day, and so on) varies significantly across verticals, merchants need to have a firm understanding of their customers before enabling these checks. Velocity thresholds should be set at the threshold at which customers go from standard behavior to fraudulent behavior.
Velocity Rules are calculated at the merchant account level. If a merchant has several merchant accounts under their company account, velocity counts do not aggregate across the entire company.
For example: A single credit card is used for 2 transactions in merchant account A and 3 transactions in Merchant Account B. The Velocity Rule counts 2 in Account A and 3 in Account B.
An abandonment of the shopper after redirecting to a payment method or 3D Secure is counted as an attempt and adds to the count for velocity rules. Not all of these abandoned attempts can be found in the payment list since this list only contains authorized and refused payments.