USPTO to Issue New Trademark Serial Number Series

The United States Patent and Trademark Office announced that a new series of trademark application serial numbers will begin on July 18, 2026. Applications filed under Sections 1 or 44 of the Trademark Act will receive eight-digit numbers beginning with 50.

The change addresses the nearing exhaustion of the current 99-series. Serial numbers will remain eight digits long, and an application's filing date and time will continue to determine priority.

Special series such as the 79-series for Madrid Protocol filings remain unchanged. The agency emphasized that examination timing and other processes are not expected to shift.

Trademark practitioners have noted potential impacts on docketing systems and internal records that assume ascending serial numbers correspond to newer filings.

Sources: https://www.uspto.gov/subscription-center/2026/new-serial-number-series-begins-applications https://www.facebook.com/uspto.gov/posts/a-change-is-coming-to-trademark-application-serial-numbersstarting-july-18-2026-/1432205592278578/