I have two overseas issued cards that are giving like 5-8% cashback on supermarket purchases.

Once I used one card at Walmart one day, I did get cashback, but when I used another card at another Walmart I did not get anything because the bank is telling me that the transaction is coded as 'discount stores' not supermarkets.

So my questions are:

- Are all Walmarts using the same MCC or it could vary?
- Do MCC at the same store (like Walmart) vary if one uses a self-checkout counter vs a manned counter?
- What are MCCs for other stores like Walmart - Smart&Final, Costco, etc?

Thanks