Card issuer
Citi
Citi operates the ThankYou Rewards currency, earned by the Strata Premier/Strata Elite cards (and the predecessor Premier/Prestige). Citi also issues co-brand cards for AAdvantage and Costco.
Cards that earn Citi ThankYou Rewards
Points pool into Citi ThankYou Rewards — transferable to airline + hotel partners.
Co-brand cards Citi issues
These earn the partner’s points directly — not Citi’s flexible currency.