Abstract: A network includes an account status system for checking the status of checking accounts used to make payments, and a payment account monitoring system that includes linking files that store, for individual credit card accounts, the account numbers for checking accounts used to pay the credit card accounts. The monitoring system periodically retrieves checking account numbers from the linking files and checks the account numbers at the status system. If a negative status is indicated at the status system, an alert is provided to the credit card company.

Abstract: Systems, methods, and databases for authenticating negotiable instruments comprise receiving, at an authentication system, a plurality of data values associated with a negotiable instrument, the plurality of data values including an image security feature and an account. The method further comprises obtaining account decoding information from an account verification databases, the account verification database including decoding information for each of a plurality of financial institutions; decoding the image security feature using the account decoding information; obtaining one or more verification values from the decoded image security feature; comparing each of the verification values to a corresponding one of the data values; and transmitting a result communication indicating a result of the comparison.