This report explores the problem of “cluttering” of trade mark registers. The report consists of two parts: the first presents a conceptual discussion of “cluttering” of trade mark registers. The second part provides an exploratory empirical analysis of trade mark applications at the UK Intellectual Property Office (UKIPO) and the European trade mark office (OHIM). This part contains results of a descriptive and an econometric analysis. According to our definition, cluttering arises where firms hold trade marks that are overly broad or unused raising search costs for later applicants. The report distinguishes between three mechanisms that can lead to cluttering. It also considers a series of mechanisms that work against cluttering. This discussion is based on a review of the previous literature. The tentative empirical evidence provided in the second part of the report suggests that trade marks are more frequently registered in several classes at the same time and also that firms in pharmaceuticals increasingly resort to multiple simultaneous applications to ensure that they will register at least one trade mark. There is also some evidence that firms seek to avoid mechanisms such as relative grounds examination which can prevent cluttering. Finally, we report direct survey-based evidence that applicants perceive cluttering to be a problem in specific fields and countries. However, our exploratory analysis does not provide strong evidence that cluttering has already become a systemic problem for the trade mark systems that is comparable to the effect of patent thickets for patent systems
