Copyright and moral rights to this thesis/research project are retained by the author and/or other copyright owners. The work is supplied on the understanding that any use for commercial gain is strictly forbidden. A copy may be downloaded for personal, non-commercial, research or study without prior permission and without charge. Any use of the thesis/research project for private study or research must be properly acknowledged with reference to the work's full bibliographic details.This thesis/research project may not be reproduced in any format or medium, or extensive quotations taken from it, or its content changed in any way, without first obtaining permission in writing from the copyright holder(s).If you believe that any material held in the repository infringes copyright law, please contact the Repository Team at Middlesex University via the following email address:eprints@mdx.ac.ukThe item will be removed from the repository while any claim is being investigated. Using company accounts data for 5 countries (US, UK, Japan, France and Germany) we analyse the relationship between intangible assets and productivity. We integrate the company data with industry information on tangible and intangible investments and skill composition of the labour force. The industry data are summarised in two different taxonomies, factor and skill intensive groups, which account for differences in the knowledge intensity and innovative activities within sectors. The results provide evidence of higher productivity in R&D and skill intensive industries. This can be interpreted as evidence in favour of the presence of spillover effects.