This paper provides novel empirical evidence on the private value of patents and R&D. We analyze an unbalanced sample of firms from five EU countries- France, Germany, Switzerland, Sweden and the UK in the period 1985-2005. We explore the relationship between firm’s stock market value and patents, accounting for the ‘quality ’ of EPO patents. We find that Tobin’s q is positively and significantly associated with R&D and patent stocks. In contrast to results for the U.S., forward citations do not add information beyond that in patents. However, the composite quality indicator based on backward citations, forward citations and the number of technical fields covered by the patent is informative for value. Software patents account for a...