What Is a Primary Account Number?

A primary account number is a 14, 15 or 16 digit number generated as a unique identifier designated for a primary account. Some accounts may have secondary account numbers associated as subsets of an account or given to secondary account holders. In some cases, the primary account number may be the only number associated with the account, thereby simply being called the account number.

Primary Account Number Explained

Primary account numbers are a unique identifier that supports account record keeping and resolution if issues should arise with the account. The primary account number is typically generated when an account is opened. Therefore, it is usually the first account in a series of accounts that may be opened by a customer at a financial institution. The primary account number is also usually the number identified with a tradeline on an individual’s credit report.

Both debit and credit cards may possibly be issued to a secondary account holder if authorized from the primary account. If an account has a secondary account holder, cards issued to the secondary user may have a secondary account number, or both users’ cards may use the primary account number, depending on the financial institution’s card-issuing policy. In contrast, a business credit card account might have a primary account number that doesn’t appear on any employee’s credit card, and secondary account numbers that appear on each employee’s card.

Primary Account Number Identifiers

You can learn a lot from a primary account number if you understand the method behind its creation. The very first digit is called the major industry identifier and it identifies the type of credit card. American Express cards start with a 3, Visa cards start with a 4, MasterCard cards start with a 5, and Discover cards start with a 6. Certain airline credit cards start with a 1 or 2, petroleum company cards start with a 7, and certain telecommunications and healthcare cards start with an 8.

The first six digits identify the credit card network associated with the card, such as 601100 for Discover cards. The last digit is a checksum number, which helps prevent criminals from creating fraudulent credit card numbers. The numbers in between the first six digits and the last digit uniquely identify the customer’s account.

Primary Account Number Precautions and Legislation

Credit card companies such as Visa ask merchants to take precautions to protect customers’ primary account numbers. One such guideline is called PAN truncation. Visa says that merchants are not required to store full account numbers, since doing so presents a security risk if there is a data breach. In the United States, a federal law called the Fair and Accurate Credit Transactions Act of 2006 prohibits merchants from printing more than the last 5 digits of a cardholder’s account number on a receipt. Merchants are also prohibited from printing the card’s expiration date.