What is Likelihood of Confusion Between Trademarks?

Basic Legal Concept: 

Under Section 2(d) of the Lanham Act, the Patent and Trademark Office (PTO) may refuse to register a trademark that is so similar to a registered mark as to be likely, when used on or in connection with the goods of the applicant, to cause confusion, or to cause mistake, or to deceive. Whether a likelihood of confusion exists between an applied-for mark and a prior mark is determined on a case-by-case basis applying the thirteen non-exclusive factors set forth in DuPont. Not all of the DuPont factors are relevant to every case, and only factors of significance to the particular mark need be considered. For example, the Trademark Trial and Appeal Board can focus on dispositive factors, such as similarity of the marks and relatedness of the goods.

DuPont Factors:

(1) The similarity or dissimilarity of the marks in their entireties as to appearance, sound, connotation and commercial impression.

2) The similarity or dissimilarity and nature of the goods or services as described in an application or registration or in connection with which a prior mark is in use.

(3) The similarity or dissimilarity of established, likely-to-continue trade channels.

(4) The conditions under which and buyers to whom sales are made, i.e. “impulse” vs. careful, sophisticated purchasing.

(5) The fame of the prior mark (sales, advertising, length of use).

(6) The number and nature of similar marks in use on similar goods.

(7) The nature and extent of any actual confusion.

(8) The length of time during and conditions under which there has been concurrent use without evidence of actual confusion.

(9) The variety of goods on which a mark is or is not used (house mark, “family” mark, product mark).

(10) The market interface between applicant and the owner of a prior mark:

(a) a mere “consent” to register or use.

(b) agreement provisions designed to preclude confusion, i.e. limitations on continued use of the marks by each party.

(c) assignment of mark, application, registration and good will of the related business.

(d) laches and estoppel attributable to owner of prior mark and indicative of lack of confusion.

(11) The extent to which applicant has a right to exclude others from use of its mark on its goods.

(12) The extent of potential confusion, i.e., whether de minimis or substantial.

(13) Any other established fact probative of the effect of use.

In re E. I. Du Pont de Nemours & Co., 476 F.2d 1357 (C.C.P.A. 1973)