Amex said Costco was 11% of their business (that breakup must have been really acrimonious), so I don't doubt that Citi is going to have scaling problems on-boa

Amex said Costco was 11% of their business (that breakup must have been really acrimonious), so I don't doubt that Citi is going to have scaling problems on-boarding that many new customers at once. It took a visit to the membership desk to get mine to work. Oh, and as a former Citi customer, if it weren't for that 4% back on gas purchases, I would be using someone else's card at Costco (you can use a membership card + any Visa-branded card there now).