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Merchant Identification Numbers 101

Credit card processing is essential to brick-and-mortar businesses, and even more so to online businesses. Keeping a customer’s financial information private is paramount. Each merchant has a specific, unique identification number that facilitates timely and secure processing.

Credit card processing involves many variables that keep transaction information safe and secure. On top of ensuring these transactions are credited to the right accounts, they must also run through the right networks.

What Is a MID?

Every merchant is assigned a merchant identification number (MID) to use when processing credit cards. This unique identifier is given to merchants by their payment processor. It is transmitted with cardholder information to facilitate transaction reconciliation. The MID helps identify the merchant when communicating with their processor and other parties.

Merchants receive their MID from the financial institution or bank that maintains the merchant’s bank account. This institution is often referred to as the acquiring bank, merchant bank, or acquirer. The acquiring bank sends the merchant’s transaction to the applicable issuing banks for payment.

The MID is critical since there are millions of businesses throughout the world that process credit card transactions. Banks use this number to identify each merchant and route their transactions through the proper channels.

How to Get a Merchant ID Number

A MID is issued automatically when a merchant opens an account with a credit card processor. The MID is located on any statement provided by the merchant. If it isn’t on the statement, it can be requested from customer service or found in a directory of MIDs.

Note that you don’t get a MID if you are using a service such as Square or PayPal to process payments. These services don’t require a formal merchant account to use them. When you work with standard merchant bank to accept payment, you’ll need a MID.

However, you do get a MID with a self-service kiosk. Self-service kiosks allow businesses to process credit card payments and complete transactions without human intervention. Self-checkout and self-services are becoming increasingly popular in all verticals, from grocery stores to fast-casual restaurants. Payments made with this technology are treated as any other card processing transaction and follow the same protocols to keep them safe and secure.

Can a Merchant Have Multiple MIDS?

A merchant can maintain multiple MIDs if they process their transactions through multiple credit card processors. This scenario is possible if a merchant uses one credit card processor for their domestic account and a different one for their international payments.

Keeping MIDs Secure

Merchant identification numbers, merchant account IDs, and all other identifying information should be kept secured. Otherwise, they can be used to create fraudulent transactions. All of these ID numbers are used to ensure that transactions route correctly and that they are legitimate. MIDs should be entered into POS systems and only be accessible to people in the company that absolutely have to have it so that they can complete transactions.