Research Guides: Trademarks & Trade Names: Common Law Resources

Common Law Trademark Resources

Unregistered trademarks may be protected under common law rights, which are based on usage. Common law marks do not enjoy the same level of protection as registered trademarks. However, they can create problems and complications for businesses that wish to use a similar mark. Trademark ownership is based on who uses a mark first, so it is a good idea to search common law marks in order to avoid future conflicts and problems.

Below are useful resources and suggestions for searching common law marks.

Business Name Registeries

NUANS Name Search System
A fee-based service for searching Canadian corporate names and trademarks registered at the federal and provincial levels.
Ontario Business Name Registration/Search
A fee-based name search and registration system operated by the Ontario government.

U.S. State Trademark and Business Name Databases

It is possible to register a state trademark in all fifty states. Although state trademarks are relatively weak compared to federal trademarks, they can cause unexpected problems. If you intend to do business in one or more states, it's a good idea to include state trademarks in your clearance search.

U.S. State Trademark Information (USPTO)
A list of state trademark and trade name databases maintained by the USPTO.

Business Directories and Yellow Pages

Directories of Canadian Companies
A collection of directories of Canadian companies maintained by Agriculture and Agri-Food Canada and Innovation, Science and Economic Development Canada.
ThomasNet (Thomas Register)
A leading directory of North American manufacturers, distributors and service providers.
YellowPages.ca
Search more than 1.5 million businesses across Canada.
YellowPages.com
Search 20 million business listings across the U.S.

Internet Domain Name Registeries

ICANN WhoIs
Internet domain search operated by ICANN, the non-profit Internet Corporation for Assigned Names and Numbers.
WHOis.net
Internet domain search maintained by NTT Communications.