Secondary trademark register for the USPTO. It allows for registration of certain marks that are not eligible for registration on the Principal Register, but are capable of distinguishing an applicant's goods or services. Marks registered on the Supplemental Register receive protection from conflicting marks and other protections, but are excluded from receiving the advantages of certain sections of the Trademark Act of 1946. The excluded sections are listed in 15 U.S.C. S1094.
If the applicant seeks registration on the Supplemental Register, the application should state that registration is requested on the Supplemental Register. If no register is specified, the Office will presume that the applicant seeks registration on the Principal Register. To register a mark on the Supplemental Register, applicants must either be using the mark or filing under Trademark Act Section 44 based on a foreign registration.
Source: U.S. Patent and Trademark Office.