Company Category Codes from Visa
Many credit cards give different rewards based on the type of purchase, for instance, the American Express Blue Preferred gives you 6% cashback on your grocery store purchases.
It can be confusing figuring out how a company is going to be categorized until you shop there.
For example, how is a Walmart that has groceries categorized?
Visa has a tool that can help. They have a website that helps companies figure out how their supplier is categorized. Just put in the store you are interested and the city and it should come up.
I found out that my local Walmart is considered to be just as much a grocery store as my local supermarkets! I will have to use my AMEX Blue Preferred there to see if I will get my 6% back. Walmart often has good gift cards so I may be able to get 6% back on those as well!
I'm sure there will be errors so don't spend hundreds of dollars based on this list, try it out with a small amount first, but you may find that there are stores that qualify for extra bonuses that you didn't know about