A billing system for use in a telephone signaling network. The network comprising offices through which telephone calls can be routed, each office being owned by a telephone company that participates in the network. Each office includes a signaling point (SP) that includes means for formulating message signaling units (MSUs). An MSU may comprise a query requesting a call data pertinent to a particular call, for example, for verifying the validity of a credit card number. The network also includes signal transfer points (STPs) for receiving and routing the MSUs, and plurality of service control points (SCPs), each SCP being linked to one of the STPs. Each SCP comprises a database that includes call data provided by one or more of the participating telephone companies. The billing system of the invention includes means for capturing at least a portion of the MSUs received by one or more STPs. The billing system processes the MSUs to produce usage data that indicates service recipients and service providers. The service recipient is the telephone company that owns the SP that formulated the MSU, and the service provider is the telephone company that provided the call data for the MSU, or that transported the MSU. The usage data may then be used to produce invoice data for accurately assigning costs among the telephone companies.