A managed service for the detection of fraud and/or anomalous transactions is disclosed. In one implementation, the managed service receives data from customers over a wide area network, the data for each customer relating to information that the customer would like monitored for anomalous transactions. The service may analyze data from the customers based on Benford's law to detect potential anomalous transactions in the data from the customers. The managed service may further report occurrences of detected potential anomalous transactions to the customer.