®
is the symbol of a registered U.S. trademark or
of a mark registered in certain other countries. ^[3]

Unlike the © symbol in a copyright notice, the ® symbol may not be used with a trademark in the U.S. until a Certificate of Registration has been issued by the U.S. Patent and Trademark Office, or unless the mark is registered in a nation in which ® is the symbol of national registration.^[3] This is matter of law (15 USC §1111) which establishes ® and certain alternatives as the proper means to provide public notice of trademark registration. The alternative notices are the legends "Registered in the U.S. Patent and Trademark Office" and "Reg. U.S. Pat. & Tm. Off." None of these notices may be used with unregistered trademarks or with state-registered trademarks.

Improper use of ® and the alternative notices may be construed as fraud, and particularly fraud upon the Patent and Trademark Office. Such fraud may result in federal criminal charges and may affect the validity of rights in a trademark.

The other side of the coin is that trademark owners are obligated to provide public notice of registration. Although registration alone is evidence of the assertion of ownership for most purposes of protecting the rights in a mark, the law provides that failure to use the ® symbol or the alternative notices may preclude the recovery of any damages from an infringement of the mark.

Public notice is also prudent in the case of an unregistered or a state-registered trademark. Even before aquiring a federal registration of a mark, TM (or the word "Trademark") for trademarks or SM (or the words "Service Mark") for service marks should appear in every use of the mark. Failure to provide public notice of a claim of ownership of a mark can affect the rights that may be claimed in that mark, can even affect the ability to register the mark at all, and affects the ability to claim damages from infringements of the mark. Public notice is an important issue.