Bright Line Trademark Rule on Likelihood of Confusion

I’m a sucker for the predictability of a bright line rule, and Camilla Hrdy at the Written Description blog describes a possible de facto rule about the likelihood of confusion in trademark cases:

In trademark law, infringement occurs if defendant’s use of plaintiff’s trademark is likely to cause confusion as to the source of defendant’s product or as to sponsorship or affiliation. Courts across circuits often frame the question as whether an “appreciable number” of ordinarily prudent purchasers are likely to be confused. But evidence of actual confusion is not required. There is not supposed to be a magic number. Courts are supposed to assess a variety of factors, including the similarity of the marks and the markets in which they are used, along with evidence of actual confusion, if any, in order to asses whether confusion is likely, at some point, to occur. 

In theory.

But in practice, Bernstein asserted, there is a magic number: it’s around fifteen percent. Courts will often state that a survey finding 15% or more is sufficient to support likelihood of confusion, while under 15% suggests no likelihood of confusion.

Likelihood of Confusion: Is 15% The Magic Number?

There are of course many confounding factors including whether this 15% applies to “gross confusion” (total confusion that includes noise from other factors) or “net confusion” (caused only by use of the trademark), and problems with survey evidence in general. But I’ll briefly fantasize about being asked what “likelihood of confusion” means in trademark law and answering, “15%. It’s just 15%.”

Fed. Cir. Permits Trademark Registration with “De Minimis” Sales: Christian Faith Fellowship v. Adidas

A unanimous Federal Circuit panel concluded that the sale of just two hats across state  lines will trigger the “use in commerce” provision for purposes of trademark registration.

A prerequisite for Federal trademark registration under the Lanham Act is “use in commerce.” But is there some minimum threshold, like “substantial use”?

Nope. The decision reviews Commerce Clause jurisprudence (including the infamous Wickard v. Filburn teaching case about a farmer growing wheat for personal use) and finds that even small sales are “part of an economic ‘class of activities’ that have a substantial effect on interstate commerce.” That’s all that’s required.

Meeting the “use in commerce” test for Federal trademark registration isn’t that difficult.