What your credit card says about you

Most people have shopped online with a credit or debit card and these days we barely think before using the plastic. But, the credit card details we put in don’t just make purchases. They can also tell us a lot about the banking habits of the user, information such as town of origin and even fraud risk.

Anatomy Of a Credit Card Number

(Note: this goes for most modern debit cards as well)

MII – Master Industry Identifiers

The very first digit of the long string on your credit card is the master identification number, it tells you which industry the card originated from

• 0 ISO/TC 68 and other industry assignments
• 1 Airlines
• 2 Airlines and other industry assignments
• 3 Travel and entertainment
• 4 Banking and financial
• 5 Banking and financial
• 6 Merchandising and banking
• 7 Petroleum
• 8 Telecommunications and other industry assignments
• 9 National assignment

Some cards may not appear where you expect, but are there for historical reasons. For example, American Express is in Travel and Entertainment, rather than banking.

Another slightly odd one out are Best Buy Credit Cards in the United States, which start with a 7 (I have no idea why Best Buy thinks it’s in the Petroleum industry, but I suspect as it’s an HSBC white labeled card, HSBC owned a company that use to issue under these numbers.)
Just with the first digit we can tell:

• If the card is a VISA card (they all start with 4)
• If they are a specialist business card 0,1,7,8,9
• If they are a second tier (normally debit cards) 6

BIN – Bank Identification Number

Sometimes called IIN (Issuer identification number) this is the first 4 or 6 digits of the card including the MII at the front. With this number you can identify the Issuing party, normally a bank. For example, 4047 83 is NatWest Private Banking Visa Credit Card.

Thinking it is just restricted to Credit and Debit cards? Think again! 6034 50 is Starbucks Card (for Starbucks Europe).

The complete BIN list is kept a closely guarded secret. While the reason normally cited for keeping the list a secret is security by obscurity, it’s more likely simply to protect ISO Registry and American Bankers Associations who publish the list. Bottom line.

There are however numerous attempts to identify all cards a short list can be found on Wikipedia and a larger BINDatabase is also available, which is user contributed. As you would expect, much like postcode data here in the UK, there are people selling copies of the data, but these lists may or may not be genuine so buyer beware.

Checksum

The last digit of the big long number is a checksum. This provides a quick way to validate the credit card number. While not useful in profiling the user, it’s worth noting all modern credit debit cards (including Laser Cards (contrary to Wikipedia) use Mod10 or Luhns Algorithm.

Expiry Date and Sort Code/Issue Number

All Credit Cards have an expiry date and some also include a start date. Using the two numbers and the current date can be used to help determine a risk assessment on the cards. Newer cards will be of a greater risk of charge backs and issues. Older cards are more likely to be hitting credit limits and be maxed out.
Some debit cards have a 6 digit Sort Code (mainly in the UK). The first 2 digits indicate the issuer, much like the BIN number. The last 4 digits are for internal use only, but basically are branch & handling office identifiers. So, for example, 52-41-19 is NatWest, Woolpack Ely Branch.

Getting hold of a list is not easy, as there is no centralised database, but with this date, you know the location of the card holders when they opened their bank accounts. People move; their sortcodes normally don’t.

Issue Number, again, mainly on debit cards, shows how many of that type of card they have had. For example, if a user had a solo card, then was given a switch/maestro card, the issue number on the Switch card would be 1. An issue number could potentially be a way of validating long term stable credit rating, but probably unreliable as such.

Potential Uses For Credit Card Data?

Identifying High Value Customers

Let’s face it: we don’t all have platinum cards in our pockets (well if your card starts 3713 then you do), but just like in a shop, the colour of your credit card often affects your experience. In the online world, it can be the same.

Ecommerce data miners looking for high value customers and can identify more premium credit cards such as the Platinum American Express (3713), Black Card (uk: 3742 88) or Infinite Aerogold (4500 03). There are plenty of others, just remember all that glitters is not gold! There are plenty of gold & platinum cards out there with low limits and anyone can max out their card!

Identifying Fraud Risk/Spending Profiling

Some banks are going to be more likely to have a higher rate of charge backs. In the UK, store cards, most of which are credit cards rather then loyalty cards, have a higher risk of chargeback against them. This can be put down to:

• Targeting people with bad or low credit score
• Lots of pressure from sales staff to push the cards

Likewise, there are certain banks that are likely to have a different approach to risk assessment when offering credit. While it would be unfair to assume all transactions will be fraudulent from these providers, it could be used in any risk calculations. In addition, you can use card types within profiling.

One example is something I’m working on now, which is a donation system where users may select how much they want to pay. When we see a high value platinum card making a $1 donation, it is deemed far more suspicious than if they were making a $50 or $1000 donation. Likewise, if a solo card made a $1000 donation, we would consider that outside of the normal profiling.

Just Being Nosy

When you combine this information with other buyer mining, you can come up with quite a comprehensive overview of a user. Their credit card choice and postcode is enough information along with demographic information from the Acorn Database (for those in the UK)  to make a rough judgment of an individual.

So, next time you use a credit card, ask yourself how much does your card say about you?