Enterprise resource planning (ERP) systems are ubiquitous in commercial enterprises of all sizes and invariably need to account for the notion of value-added tax (VAT). The legal and technical difficulties in handling VAT are exacerbated by spanning a broad and chaotic spectrum of intricate country-specific needs. Currently, these difficulties are handled in most major ERP systems by customising and localising the native code of the ERP systems for each specific country and industry. We propose an alternative that uses logical modeling of VAT legislation. The potential benefit is to eventually transform such a model automatically into programs that essentially will replace customisation and localisation by con¿guration by changing parameters in the model. In particular, we: (1) identify a number of requirements for such modeling, including requirements for the underlying logic; (2) model salient parts of the Danish VAT law in Web Ontology Language (OWL) and in Con¿git Product Modeling Language (CPML).