IT resources support the value generation process of an organisation by enabling or facilitating business processes activities execution. Due to nowadays complexity of IT infrastructures, identifying how IT resources impact on value generating activities is not easy. The identification of IT resources affecting value generating activities is suggested as a promising direction for deepening the understanding of the IT Business Value phenomenon, an area with a long-standing tradition in IS research. So far, no generally applicable methodology is available in literature to target the problem of the identification of the impacts of IT resources on value generating activities. With the intent to provide an artefact that can be used for such purpose, this paper introduces an ontology-based approach. The ontology proposed here originates from two ontologies available in literature (the Business Model Ontology and the OLPIT ontology). The two sources ontologies focus partially on the problem in discussion, but are not capable when taken alone to solve it. In the frame of a design research activity these ontologies have been integrated in the IT-BM ontology. A test case based on a practical real life scenario is presented in the paper to illustrate its applicability. The paper also discusses possible benefits connected with the adoption of such an approach, along with its current limitations and its possible improvements.