An unregistered trademark in a “common law country,” i.e., a country sharing its legal traditions with England. Common law trademarks are protected under the tort of passing-off or “unfair competition.” Common law marks are created when a vendor sells goods or services under the vendor’s name or a brand for an extensive period of time, which it has not registered as a trademark.
If a third party seeks to sell products under that mark or brand without permission of the original vendor it may be liable to the original vendor for damages, notwithstanding the lack of a formal trademark registration. Common law marks exist because in most countries, formal trademark laws evolved after the tort of “passing off” already existed and it was not subsequently abolished. One risk in distribution systems is that when a supplier had failed to register the trademark locally, their local distributor may come to have “common law” rights to the mark, which can prove problematic if the distributor is terminated.