A cardholder authentication computing device for authenticating user computing devices during online payment transactions are provided. The cardholder authentication computing device leverages pre-authentication of a user by a private network to facilitate authentication of a user in the context of an online payment transaction between the user and a merchant. During the course of an online payment transaction, the cardholder authentication computing device may receive an authentication request messages containing pre-authentication data from a merchant computing device. The cardholder authentication computing device then authenticates the user based, in part, on the pre-authentication data. In certain embodiments, the cardholder authentication computing device may also determine whether one or more partner services apply to transactions between the user and the merchant based on the user's affiliation with the organization.