This will most likely come down to a few issues.

1. financially what makes the most sense for Doug Parkers new combined airline.

2. Which contract has the fewest onerous exit clauses.

If it makes economic sense to keep both Citi and Barclays that will happen.

If after helping AA during bk by buying $1,000,000,000 worth of frequent flyer miles from American; Citi placed some exclusivity clauses in the contract, the ultimate victor may be driven by that.

It appears to me that Citi has stronger ties with American than does Barclays with US. But again, AA/US probably have their attorneys reviewing every word of each contract to see what/if any, the penalties are for ending each contract, and if there are merger clauses in the cards contracts.

I think this one will be in the attorneys hands for awhile and then the negotiations with each of the card companies will begin in earnest, once all of the options based on contractual commitments are fully understood by US/AA. This will take months. So any communications from the card companies until the end of this process will be pacification on their part.