Visa, in it's merchant regulations, very clearly requires that the word "VISA" be printed on all transaction receipts. Mastercard, as far as I can tell, is silent on the topic. They neither require nor prohibit the practice. I am trying to find any kind of regulation, notification or other official mastercard document which requires the word "Mastercard" on merchant receipts. This is imporant - I am working on a legal matter. Thanks very much for any enlightenment you can provide.