A "credit card merchant audit" is a process of reviewing and analyzing the credit or debit card transactions and fees of a business that accepts card payments¹⁵. The purpose of a credit card merchant audit is to identify and reduce hidden fees, excessive rates, inaccurate surcharges, and other errors that may inflate the merchant's processing costs¹²⁵.

A credit card merchant audit can be performed by an independent firm that specializes in this service, or by the card networks (such as Visa and Mastercard) or the bank or processor that provides the merchant account²⁴. An independent firm can help the merchant negotiate lower fees and rates with their current provider, or switch to a more suitable one²⁵. 

A card network or a bank or processor can initiate an audit of a merchant's account if they suspect that the merchant is a high-risk one or is processing invalid transactions, such as fraud, chargebacks, or non-compliance with card network rules⁴. A card network or a bank or processor audit can result in fines, penalties, account suspension, or termination for the merchant⁴.

(1) How Does A Credit Card Merchant Fee Audit Work?. https://merchantcostconsulting.com/lower-credit-card-processing-fees/how-does-a-credit-card-merchant-fee-audit-work/.

(2) Merchant Account Audit Process - Verisave. https://verisave.com/merchant-account-audit-process/.

(3) Contingency-Based Merchant Services Auditing Firm| IMG Audit. https://imgaudit.com/.

(4) Merchant Audit: Initiation, Review Process and Consequences. https://blog.unibulmerchantservices.com/merchant-audit-initiation-review-process-and-consequences/.

(5) Credit Card Related Merchant Activities Core - FDIC. https://www.fdic.gov/regulations/safety/manual/section22-1/sc-ccrma.pdf.