A resurgence of interest in ontology emerged in the 1990s from the field of information systems engineering. From beginnings such as the Cyc project to codify commonsense knowledge and the Stanford Knowledge Sharing Laboratory efforts to build a shareable ontology of terms, emerged a multitude of ontologies, academic contributions, conferences and commercial companies. / However, does "applied ontology", as a joint field between information systems engineering and philosophy, actually exist? A field that equally informs both engineering and philosophical ontology has obstacles to overcome. For example, according to Grüber's (1993) ubiquitous definition, engineering ontology is a "specification of a conceptualization", whereas in philosophy an ontology is "a systematic account of Existence" - a significant difference. Furthermore, there are philosophical objections to ontology that may undermine its practical application. In this dissertation, we aim to overcome these obstacles by approaching engineering requirements analysis through a particularist metaphysics. More specifically, we argue that engineering 'requirements analysis' can be approached through the ontological question "what exists when the requirements are satisfied?" This approach to requirements analysis forms the core of a joint engineering and philosophical ontology. / The argument obligates us to demonstrate an example of the ontological approach to requirements analysis. We select 'Competitive Intelligence' (CI) as a commercial practice where engineering requirements lend themselves to ontological analysis. A working definition for CI emerges as being "the integration of piecemeal information to support organisational strategy". The major part of the dissertation is a formal analysis (using logic programs) that demonstrates a modified version of this definition can be coherently expressed and used to show the existence of CI as such. The logic also shows CI, as defined, supervenes on other information systems, and depends mainly on a strategic framework. / As such, for the research at hand, the analysis suffices as foundation of an ontology of CI, demonstrates the use of ontology as a requirements analysis approach, and develops a practice of applied ontology that equally informs engineering and philosophy.