To Mastercard, chargebacks are detrimental to their brand. To track these chargebacks and keep lax merchants in check, Mastercard developed a multi-tier program that utilizes chargeback ratios.
Chargeback ratios are the number of chargebacks a merchant receives in the current month divided by the total number of Mastercard transactions processed in the previous month.
A merchant that racks up at least 100 chargebacks and has a 1.5% chargeback ratio is labeled an Excessive Chargeback Merchant. If the numbers escalate to 300 chargebacks with a 3% ratio, they are labeled a High Excessive Chargeback Merchant.