A method of performing operations on a processor of a mobile payment transaction processing system, includes receiving mobile payment messages from a point-of-sale (POS) terminal operated by a merchant performing mobile payment transactions with mobile terminals. Each of the mobile payment messages contains transaction information, a network address for the POS terminal, and a geographic location provided by the mobile terminal. A POS terminal risk score is generated based on similarity between the geographic locations provided by the mobile terminals contained in the mobile payment messages which also contain the network address for the POS terminal. Processing of another mobile payment message, which is received from the POS terminal performing another mobile payment transaction with another mobile terminal subsequent to the generating of the POS terminal risk score, is controlled based on the POS terminal risk score and transaction information contained in the another mobile payment message. Related comput
