I solemnly swear that I am up to no good.
J.K. Rowling’s Harry Potter series may technically be over, but that is not stopping Warner Bros. (the owner of the franchise’s rights) from continuing to profit from the magical world of Muggles and wizards. Theme parks, studio tours, a Cursed play, the new Fantastic Beasts series, several versions of the books, a plethora of merchandise, and so much more have brought in an estimated $25 billion for Warner Bros. and the company who owns Warner Bros, Time Warner, since 1998.
While JK Rowling wrote the books and played a part in the production and direction of the movies, Warner Bros. bought the rights to Harry Potter and still holds the copyrights and trademarks that go along with the original purchase of the ever-growing franchise. Along with these intellectual property rights, Warner Bros. has the power to develop new trademarks—a power which they continue to take advantage of to this day.
The Warner Bros. logo is synonymous with Harry Potter merchandise at this point.

Fans of the movie (or those naturally exposed to it) have heard one of the more mischievous quotes first said by the Weasley twins: “I solemnly swear that I am up to no good.” In the series, these words unlock a magical map, showing characters’ whereabouts in the Hogwarts fortress, but Warner Bros. was hoping that this would unlock something else: a monopoly on merchandise featuring the quote (to of course, sell on the likes of Amazon and in Universal Studios).
Unfortunately for the studio, Warner Bros.’ initial trademark application was rejected and the U.S. Patent and Trademark Office (“USPTO”) issued an Office Action (“OA”). OA’s are not uncommon in the trademark world and can be issued for a number of reasons, including a likelihood of confusion (with another mark) or, in this scenario, drawing a false connection or association to the author and merely being an informational slogan. The trademark applicant (Warner Bros.) has an opportunity to respond to the OA within six months. If the USPTO believes the applicant has overcome the reasons for rejection, it may then accept the response and the trademark.
The popularity of the quote has sparked an array of fan-created products on websites such as Etsy, ranging from t-shirts to coffee mugs, including jewelry, dog collars, household prints, key chains, and diaper cloths. If Warner Bros. is granted the trademark, the company would have the ability (and responsibility) to “police” its mark. This would require Warner Bros. to send out cease-and-desist letters to all of the creators and would even give the company priority of the mark over its true creator: J.K. Rowling.
Update: Warner Bros. was able to overcome both issues by showing that: (1) the studio’s ownership of the mark does not create a false connection or association with J.K. Rowling; and (2) the mark is not merely an informational slogan incapable of functioning as a trademark. As discussed above, this means that the many products featuring “I solemnly swear that I am up to no good” will now be subject to Warner Bros.’ policing of the mark. If the studio’s history is any indication, the fan-creators should expect cease-and-desist letters in the near future.
[This article was prepared by Abbie Cook, our intellectual property research apprentice.]