How can one find a trademark's serial or registration number?

Finding a trademark's serial or registration number is efficiently achieved through the Trademark database maintained by the United States Patent and Trademark Office (USPTO). This database allows users to search for trademarks based on various criteria, including name, owner, or filing date. The search results typically provide detailed information, including the trademark's serial number (for pending applications) or registration number (for registered trademarks), along with the status of the trademark.

The other options each have their limitations. Contacting the USPTO directly may yield the necessary information, but it may not be as quick or efficient as using the trademark database, which is readily accessible online. The Assignment Recordation Branch records are primarily focused on changes in ownership and can be useful for historical data but do not directly provide serial or registration numbers in a user-friendly manner. Filing a new trademark application does not help in finding the number of an already existing trademark; rather, it initiates a new trademark registration process. Thus, the best method for retrieving a trademark's serial or registration number is indeed through the Trademark database.