In trademark law, foreclosure by tolerance refers to the loss of a trademark owner’s right to act against a third party for unauthorised use of their trademark if the owner has tolerated such use for a certain period of time without intervening. This concept is particularly relevant when the trademark owner is aware of the use of their trademark by a third party and takes no action to stop or challenge that use for five consecutive years.
This principle is governed by trademark legislation in several jurisdictions, including the European Union, where it is specifically provided that the trademark owner may be barred from exercising their rights if they have tolerated the use of the trademark by a third party for five years while being aware of such use. It aims to promote good faith in commerce and prevent situations where trademark owners could mislead other market players by allowing a trademark to be used without opposition, only to suddenly claim infringement.