Abstract: Detecting fraudulent activity can include receiving, via at least one computing device, transactional data from a first computing system, the transactional data comprising data describing at least one transaction and user identifying information. The transactional data can be determined to correspond to a particular user account. Mobile device data associated with the particular user account can be received. Based on a comparison of the transactional data to the mobile device data, a likelihood of a fraudulent event can be determined. In response to the likelihood of the fraudulent event exceeding a predefined threshold, one or more remedial actions can be performed.