American Express had an exclusive credit card products and network relationship with Costco in the U.S. from 2000 until this month. Effective Monday, June 20, more than 11 million newly issued Citi Costco Visa co-branded cards replaced all American Express Costco cards. Citi issues a Costco Anywhere Visa card for consumers and a Costco Anywhere Visa Business Card for small business owners, down from the four consumer and commercial products offered by Amex, which stopped issuing new Costco cards in the fourth quarter of 2015. American Express completed the sale of its portfolio of $10.55 bi...