Apple is currently in talks with both Barclays & Synchrony to take over the Apple credit card portfolio. Goldman has previously stopped bidding for new credit card programs and both American Express & Chase have previously been rumored to be in talks with Apple.
One issue with this portfolio is that Apple has demanded a lot of compromises from the issuing bank (little to no fees, higher than normal rev share, less stringent approval process). I suspect Apple will have to compromise with some of these to get another card issuer interested in the asking price.
