From the DMV to the deli counter at your local grocer, numbers serve as a reliable way to identify where people are in line or in order. A merchant identification number, or MID, serves a similar purpose by providing business entities with a one-of-a-kind code that establishes they have the proper clearance to begin processing credit cards. Business owners should receive this special code as soon as they sign up with their merchant account provider. MIDs establish the corroboration banking institutions and credit card processing companies need to move forward with a transaction. Additionally, MIDs can help business owners save, as processing fees are typically more affordable compared to third-party merchant accounts.