Unlike many other countries, the United States has what is called a first-to-use trademark system. That means that the first entity to use the mark within a territory acquires a right of priority to use that mark over all subsequent users in that location. This right derives under common law, and not from the act of federal registration. That is why a first user (a.k.a. "senior user") who has not registered his mark with the U.S. Patent & Trademark Office (“USPTO”), may have a right of priority to a mark you have already federally registered. If you find yourself in this situation, many issues could arise that may result in you losing your rights in that trademark.
So before you invest heavily in developing, branding, promoting, and advertising a product or service with a certain trademark, we recommend that you speak with an experienced trademark attorney and have him or her perform a comprehensive trademark search before using a mark.
For more information, please contact a trademark attorney today to setup a free 30-minute consultation.