In a significant reversal of prior court practice in Korea, the Supreme Court recently issued a landmark en banc decision that the use of a later-filed trademark registration that is similar to a senior registered mark can still infringe the senior trademark regardless of whether the later registration is first invalidated or not (Case No. 2018Da253444 decided on March 18, 2021).

The Supreme Court in previous cases had generally deferred to the Korean Intellectual Property Office's (KIPO's) determination that a particular mark is registrable (and therefore distinctive from existing registrations) and declined to find that the use of a registered mark by the registrant can constitute trademark infringement of an earlier-registered mark, even if the later mark is similar to the earlier mark, unless and until the later mark is first separately invalidated.

In the case at issue, the plaintiff Data Factory (which owned the registration "" designating computer software, computer software development, etc.) sued a data recovery company in district court for infringement of Data Factory's registered mark due to the defendant's use of the "" mark and other related marks in connection with its data recovery services. The defendant responded by filing an application to register its junior mark, and despite Data Factory's opposition, the junior mark was successfully registered due to KIPO's determination that the "DATA FACTORY" portion of Data Factory's mark lacked distinctiveness, and therefore the two marks were not similar. However, the defendant's registration was not completed until just before the district court issued its decision, and both the district court and the Patent Court on intermediate appeal found the defendant to be infringing Data Factory's mark without considering the existence of the defendant's registration of its own mark. The defendant then raised the legal issue of whether a registered mark can infringe an earlier mark to the Supreme Court.

The Supreme Court upheld the Patent Court's infringement ruling on final appeal, meaning the infringement decision is now final and conclusive. In upholding the Patent Court, the Supreme Court reasoned that under the Trademark Act, if a trademark owner's use of its trademark is in conflict with another party's prior filed or created patent right, utility model right, design right or copyright, the trademark owner is prohibited from using the registered trademark on the designated goods in conflict with the relevant rights of others without consent. In addition, the Trademark Act adopts the first-to-file-rule. Therefore, because a trademark right is another type of intellectual property right such as those listed above, and thus should be protected in a similar fashion, the Court held that the above rule should also apply to conflicts between earlier and later filed trademark registrations.

As a result of the Supreme Court's decision, it is now possible for a senior trademark owner to directly assert its trademark right against a later-filed trademark owner in the courts without having to first invalidate the later-filed trademark, as well as to seek damages for the period after the registration of the later-filed mark. This landmark decision enhances the ability of trademark owners to enforce their legitimate rights by removing the requirement to first invalidate otherwise-infringing but later-filed marks through a separate administrative proceeding before pursuing an infringement action against the infringer.