A policy-based control system for on-line financial transactions where transaction requests and associated contextual information is used by a policy-based transaction server to evaluate the allowance or disallowance of a requested transaction. The system is connected to one or more fund resources. A fund usage request, initiated by the requestor, is received by the policy-based transaction server where a set of policy rules that govern the allowance of all transactions associated with that fund resource are used to adjudicate the request. The resulting adjudicated response is transmitted back to the requestor where it is enforced, either allowing the transaction or disallowing the transaction. The policy-based transaction server may use contextual information about the fund usage request to determine allowance.