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

The UK and US trademark law permits registering single colors as trademarks. However, judges and experts have raised concerns about this law, known as the color depletion theory, which argues that it could deplete the pool of available colors. This theory suggests two issues of color depletion. First, it creates entry barriers. As more incumbents claim single colors as trademarks, there are fewer color options left for entrants. Second, color depletion leads to increased search costs. When more single colors are claimed as trademarks, the distances between colors shrink and the boundaries between color trademarks are blurred. Thereby consumers are more likely confused by similar color trademarks.

Despite extensive theoretical debates, there is a lack of empirical studies to determine whether, in reality, color depletion is severe or ignorable. This article fills the gap by examining 858 single-color trademarks recorded in the United States Patent and Trademark Office (USPTO). It is the first empirical legal research which codes each single-color trademark, maps them to a color space, and obtains the empirical evidence of color depletion. It analyzes (1) the existing color depletion percentage in each product/service class, and (3) how soon each product/service class will reach full depletion (3) the distribution of the depletion in different hue segments. The results indicate that color depletion is an emergent concern in electric and technological products, machines, pharmaceuticals and medical instruments and on the red, orange, yellow and green hue segments. The article further provides recommendations to the USPTO/courts to address color depletion.