Using identifiers on user payment instruments to identify user loyalty accounts comprises a method to store a loyalty account list associated with a user, the loyalty account list comprising one or more user loyalty accounts; associate an identifier with the loyalty account list; receive information identifying a user loyalty account associated with a merchant, the information comprising an account number for the user loyalty account and an identity of the merchant; associate the user loyalty account with the loyalty account list; receive a request for information identifying a user loyalty account associated with a merchant, the request comprising the identifier received by the merchant from a user payment instrument and an identity of the merchant; determine the user loyalty account associated with the merchant; and provide the information identifying a user loyalty account associated with a merchant.