USPTO Introduces New Trademark Serial Number Series

The United States Patent and Trademark Office began assigning trademark application serial numbers in a new series on July 18, 2026. Applications filed under sections 1 or 44 of the Trademark Act now receive eight-digit numbers starting with 50.

Filing date and time continue to determine priority. Special series such as the 79 series for Madrid Protocol filings remain unchanged. The update modernizes the agency's numbering system while preserving established priority rules.

The change applies to new filings and supports ongoing administrative efficiency at the USPTO. Applicants should use the filing date to confirm priority regardless of the new serial number format.

Sources: https://www.facebook.com/uspto.gov/posts/a-change-is-coming-to-trademark-application-serial-numbersstarting-july-18-2026-/1432205592278578/ https://www.uspto.gov/trademarks