Following calls to enhance risk-sensitivity of second generation Operational Risk-Aware Information

Systems (ORISs), this paper aims to address the lack of ontological/epistemological grounding for the

concept of Operational Risk (OR). Herein, OR is regarded both as a property of a real system and as

a representational phenomenon forming part of the core of ORIS in line with Weber’s (2003) view of

the core of IS. The paper explores how the ontological/epistemological position of the Critical Realist

philosophy of science assists in the Requirements Definition of ORISs by providing an ontology-driven

representation of the heterogeneous nature of OR. The retroductive mode of logical inference enabled

by Critical Realism supports the discovery of OR causal mechanisms when the historical data about

operational loss events is limited. The ontological/epistemological position suggested in the paper

contributes to better understanding and representation of OR, informs OR assessment in conditions of

a constantly changing socio-economical environment, and so assists in the Requirements Definition of