Patent oppositions and opposition outcomes: evidence from domestic appliance companies

This paper examines the extent and determinants of patent oppositions and opposition outcomes between the main competitors in the European market of large domestic appliances. By considering the patents issued by the EPO from 2000 to 2005, it is shown that the probability of a patent to be opposed by industry rivals is positively associated with the number of citations received and increases with company sales. The latter finding would suggest that patent oppositions are also used for strategic reasons. However, looking at the different outcomes of the opposition proceedings, it emerges that the probability of having a patent amended raises with the number of claims while the extent of company sales increases the likelihood of a revocation. Accordingly, patent oppositions do not appear to be used for pure strategic motives. This confirms that the opposition procedure adopted by the EPO is an effective mean to reduce the scope of further expensive litigation.