Systems and methods for detecting out-of-pattern transactions

A computer-implemented method implemented using a computing device including at least one memory device, a processor, and a communication interface in communication with a payment processing network, wherein the payment processing network routes electronic communications between a plurality of merchants and a plurality of issuers of payment cards issued to a plurality of account holders who have accounts with one or more of the plurality of issuers, each merchant being communicatively coupled to the payment processing network via at least one merchant computing device where account holder payment transactions are initiated, and each issuer being communicatively coupled to the payment processing network via an issuer computing device, wherein the communication interface is in communication with an inverse recommender module for receiving and detecting possibly fraudulent payment transactions by detecting out-of-pattern payment transactions by one or more of the plurality of account holders, the method comprising:

• receiving first transaction data corresponding to historical payment transactions from a predetermined time period between the plurality of account holders and the plurality of merchants, wherein the first transaction data includes, for each of the historical payment transactions, an identifier of an account associated with the respective account holder and an identifier of the respective merchant, and wherein the plurality of merchants numbers n;
• associating, using the first transaction data, the account of each account holder included in the first transactional data with pairs of merchants with which the account holder transacted business during the predetermined time period;
• populating each value (i, j) in an array data structure stored in the at least one memory device with a respective counter (i, j), the array based on the associating and comprising a merchant correspondence matrix for the predetermined time period wherein each counter (i, j) is obtained by parsing the first transaction data to count, from the plurality of account holders, a number of account holders having at least one historical payment transaction with both an ith merchant and an jth merchant during the predetermined time period, wherein each counter is associated with a merchant pair and is configured to increment when, during the predetermined time period, each respective account holder transacts with both merchant i and merchant j which comprise the merchant pair;
• generating an account holder historic transaction pattern for each of the plurality of account holders, wherein the account holder historic transaction pattern comprises n elements and each element corresponds to one of the plurality of merchants and includes a value, wherein the value represents the number of times the respective account holder transacted business with each merchant of the plurality of merchants during the predetermined time period;
• receiving, via the payment processing network from a merchant computing device of a first-time merchant of the plurality of merchants, second transaction data associated with a new requested payment transaction between an account holder of the plurality of account holders and the first-time merchant, wherein the account holder has no historical transactions in the first transaction data with the first-time merchant;
• generate an inverse recommender score for the account holder by executing a matrix-value multiplication function using at least the merchant correspondence matrix and the account holder historic transaction pattern for the account holder;
• determining, for each element of the corresponding account holder historic transaction pattern associated with the account holder, a change between the element value of the corresponding account holder historic transaction pattern and a value of a corresponding element of the inverse recommender score associated with the corresponding account holder historic transaction pattern, wherein the change in the value for the element corresponding to the first-time merchant being significantly larger than the change in values of the elements corresponding to others of the merchants indicates that the new requested payment transaction is out-of-pattern for the account holder;
• and
• transmitting an alert, via the payment processing network, to at least one of the issuer computing device or the merchant computing device for the new requested payment transaction when the new requested payment transaction is determined to be out-of-pattern with the corresponding account holder historic transaction pattern and is possibly fraudulent.

At least one non-transitory computer-readable storage medium having computer-executable instructions embodied thereon using a computing device including a processor, at least one memory device, and a communication interface in communication with a payment processing network, wherein the payment processing network routes electronic communications between a plurality of merchants and a plurality of issuers of payment cards issued to a plurality of account holders who have accounts with one or more of the plurality of issuers, each merchant being communicatively coupled to the payment processing network via at least one merchant computing device where account holder payment transactions are initiated, and each issuer being communicatively coupled to the payment processing network via an issuer computing device, wherein the communication interface is in communication with an inverse recommender module for receiving and detecting possibly fraudulent payment transactions by detecting out-of-pattern payment transactions by one or more of the plurality of account holders, the executable-instructions, when executed by the processor, cause the processor to:

• receive first transaction data corresponding to historical payment transactions from a predetermined time period between the plurality of account holders and the plurality of merchants, wherein the first transaction data includes, for each of the historical payment transactions, an identifier of an account associated with the respective account holder and an identifier of the respective merchant, and wherein the plurality of merchants numbers n;
• associate, using the first transaction data, the account of each account holder included in the first transaction data with pairs of merchants with which the account holder transacted business during the predetermined time period;
• populate each value (i, j) in an array data structure in the at least one memory device with a respective counter (i, j), the array based on the associating and comprising a merchant correspondence matrix for the predetermined time period wherein each counter (i, j) is obtained by parsing the first transaction data to count, from the plurality of account holders, a number of account holders having at least one historical payment transaction with both the ith merchant and an jth merchant during the predetermined time period, wherein each counter is associated with a merchant pair and is configured to increment when, during the predetermined time period, each respective account holder transacts with both merchant i and merchant j which comprise the merchant pair;
• generate an account holder historic transaction pattern for each of the plurality of account holders, wherein the account holder historic transaction pattern comprises n elements and each element corresponds to one of the plurality of merchants and includes a value, wherein the value represents the number of times the respective account holder transacted business with each merchant of the plurality of merchants during the predetermined time period;
• receive, via the payment processing network from a merchant computing device of a first-time merchant of the plurality of merchants, second transaction data associated with a new requested payment transaction between an account holder of the plurality of account holders and the first-time merchant, wherein the account holder has no historical transactions in the first transactional data with the first-time merchant;
• generate an inverse recommender score for the account holder by executing a matrix-value multiplication function using at least the merchant correspondence matrix and the account holder historic transaction pattern for the account holder;
• determine, for each element of the corresponding account holder historic transaction pattern associated with the account holder, a change between the element value of the corresponding account holder historic transaction pattern and a value of a corresponding element of the inverse recommender score associated with the corresponding account holder historic transaction pattern, wherein the change in the value for the element corresponding to the first-time merchant being significantly larger than the change in values of the elements corresponding to others of the merchants indicates that the new requested payment transaction is out-of-pattern for the account holder;
• and
• transmit an alert, via the payment processing network, to at least one of the issuer computing device or the merchant computing device for the new requested payment transaction when the new requested payment transaction is determined to be out-of-pattern with the corresponding account holder historic transaction pattern and possibly fraudulent.