The term “common law” indicates that the trademark rights that are developed through use are not governed by statute. Instead, common law trademark rights have been developed under a judicially created scheme of rights governed by state law. Common law rights may be afforded to any word, phrase, image, etc. that a business uses in commerce to identify itself, its goods, or its services. To declare your ownership of a common law trademark, you should add a superscript “TM” to it. Such rights are granted automatically upon use and extended to whoever can prove the first actual use of the mark in a given geographical area (e.g., within a specific state or region).

An owner may establish rights in a mark without registering the mark, simply by using it in connection with a business or product. These common law rights provide an owner with the exclusive right to use a mark within a certain geographic area based on their priority use of the mark. When a trademark owner is the first to use a mark, they are referred to as the “senior user.” Anyone who starts using a confusingly similar mark thereafter is called the “junior user.” A senior user of a common law trademark can sue a junior user if the junior user is operating in the same geographic area and using the mark in connection with the same or related goods and/or services.