Abstract. Companies use company-specific terminology that may differ from the terminology used in existing corporate ontologies (e.g. Tove) and therefore need their own ontology. However, the current ontology engineering techniques are time-consuming and there exists a conceptual mismatch among developers and users. In contrast, folksonomies or the flat bottom-up taxonomies constituted by web users' tags are rapidly created. In this paper, we present an approach that cost-efficiently derives a lightweight corporate ontology from a corporate folksonomy. We tested it on the folksonomy of a European company and first results are promising: it shows that it creates additional value to the company. Key words: ontology, folksonomy, company, added value