Last year Costco reached an agreement with Citi and Visa which called for Visa cards to become the warehouse club’s exclusive credit card network beginning in April of this year. As a result of said agreement, the relationship between Costco and American Express, whose network of cards had been exclusively accepted at Costco for years, would end. According to this The Seattle Times article, Costco has now announced they are delaying plans to switch from Amex to Visa until at least June or mid-summer.
As a result of this delay, Costco will temporarily extend its agreement with Amex. Therefore, Amex cards will continue to be accepted at Costco for at least three more months than initially expected. Apparently the delay is the result of negotiations between Amex and Citi. My guess is that they are still trying to determine what will happen to clients who have to Amex co-branded Costco card.
I do not shop at Costco, but if I did, I would probably be happy that I get at least three more months of paying at Costco with my Amex cards.