Tomorrow is the last day that American Express cards will be accepted at Costco stores. Amex lost the co-brand relationship to Citibank and Visa in a deal that has Citi overpaying and not even gaining exclusivity over Costco payments (starting tomorrow you can use any Visa at Costco, regardless of the issuing bank).
American Express couldn’t match the money-losing deal that Citi was offering — some have argued that it’s tax losses that subsidize the deal — but the change meant losing 10% of cardmembers.