Updated: Feb 24, 2022
If you're confused about common law trademarks it may be that you don't fully understand how trademarks are created. Maybe you think a trademark is created after receiving a trademark registration certificate from the United States Patent and Trademark Office (USPTO)?
Before, we jump into how trademarks are created let's define what a trademark is. A trademark is a source identifier. A trademark is created the moment a source identifier is used in interstate commerce. Thats it. Nothing more. The moment you start using your business name, logo, or slogan to identify your business a trademark is created.
A common law trademark is simply a trademark that has not been registered with the federal government. Federal registration is optional. Highly recommended, but optional.