It depends on what you're buying. I often make large purchases at wholesale construction supply companies. Electrical, plumbing, refrigeration, etc. Also things like delivered concrete, or maybe the crane company that hoisted stuff to the rooftop. Trust me, less than 20% of these types of companies take Amex, and many have to wipe the dust off the Visa card reader when I come in. I've never had an Amex card, but I've been listening to virtually everyone I know who does, complain about severe lack of acceptance for over 20 years now, especially in these markets.