Abstract: A model engine is provided for managing transactions for one or more computing devices over a network. There is provided a machine learning model trained and tested on historical transaction data including labelled fraud data, to provide a target signal indicative of a likelihood of fraud within a given transaction, generating an ensemble of decision trees. The engine further includes extracting a set of rules by traversing each tree in the ensemble of decision trees from a root node to each leaf node of the tree, each path from the root node to a particular leaf node including splitting criterion providing a rule to form a set of rules. A proactive risk management system is also provided for applying the set of rules to a new transaction and when at least one rule is met, triggering predetermined actions on at least one computing device on the network.