A message tracking computing device for identifying anomalous activity in real-time is provided. The message tracking computing device includes a memory in communication with a processor. The processor is programmed to receive a transaction dataset including a plurality of transaction records, each transaction record associated with a payment transaction. The processor is further programmed to compute, for a subset of transaction records of the plurality of transaction records, a normalized velocity score by computing a streaming mean, computing a streaming standard deviation, and computing the normalized velocity score based on the streaming mean, the streaming standard deviation, and a transaction ratio. The processor is further programmed to analyze the at least one computed normalized velocity score to detect anomalous activity, automatically generate an alert message identifying the anomalous activity, and transmit the alert message to a remote computing device.