Should We Worry about Color Depletion? — An Empirical Study of USPTO Single Color Registrations

17 Pages Posted: 16 Mar 2022 Last revised: 26 Apr 2022

See all articles by Xiaoren Wang

Xiaoren Wang

CREATe Centre, University of Glasgow; University of Dundee; OIPRC, University of Oxford

Date Written: January 18, 2022


Both the EU law and the US law allow registering single colors as trademarks. However, some judges and scholars have pointed out that this law would exhaust available colors, called "color depletion". The theory believes that trademarking single colors are problematic because first, it develops market entry barriers. Second, color depletion increases consumer search costs. When more single colors are claimed, the distances between colors shrink and the boundaries between color trademarks will be blurred. Thereby consumers are more likely confused by similar color trademarks. Despite many theoretical studies on color depletion, there are no empirical studies to test whether, in practice, color depletion is severe or ignorable. This project fills this gap by measuring the color depletion situation through thousands of single-color trademarks recorded in the United States Patent and Trademark Office (USPTO). This project will report (1) the overall color depletion and the depletion speed per year, (2) color depletion per product/service class and per color category, and (3) color congestion within the same product/service class, measured by how many new color applications are rejected by already-registered colors due to the similarity.  Based on this data analysis, the project will evaluate whether the color depletion in the US is severe or ignorable, further suggesting trademark offices, courts, and policymakers on adjusting the threshold of trademarking single colors. (The research is funded by the Creative Industries
Policy and Evidence Centre (PEC) under Arts and Humanities Research Council (AHRC) grant AH/S001298/1.)

Keywords: Color depletion, empirical, trademark law, registration, USPTO

Suggested Citation

Wang, Xiaoren, Should We Worry about Color Depletion? — An Empirical Study of USPTO Single Color Registrations (January 18, 2022). Available at SSRN: or

Xiaoren Wang (Contact Author)

CREATe Centre, University of Glasgow ( email )

9 Professors' Square
Glasgow, G12 8QH
United Kingdom

University of Dundee ( email )

Dundee, Scotland DD1 4HN
United Kingdom

OIPRC, University of Oxford

Mansfield Road
Oxford, Oxfordshire OX1 4AU
United Kingdom

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