Consumer Investment in Trademarks This article introduces the consumer investment model as means to identify and protect twenty first century consumer interests in trademarks. Section I demonstrates why this model is necessary. Protecting consumer interests is the theoretical rationale for regulating trademarks. Theory and practice meshed well when the rights of trademark owners aligned with consumers. For example, both trademark owners and consumers are harmed when marks are used on low quality counterfeit goods. In cyberspace, this neat alignment often breaks apart. Many unauthorized uses, such as keyword advertising, benefit consumers but threaten owner control over marks. In order to protect the interests of trademark owners in many new contexts, trademark law has expanded and uprooted the doctrine from its limiting principles. Trademark discourse too often casts consumers as easily confused dupes. This negative consumer construct is often used as a justification for protecting trademark owners, resulting in trends that ignore or harm actual consumer interests. Current theoretical approaches do not provide an adequate mechanism for recognizing consumer interests in marks and protecting them. In order to bring public interests back into trademark jurisprudence, Section II proposes the consumer investment model. Its central principle is that the public invests marks with meaning and value, and therefore, is due a return on that investment. This Section tears down two outdated assumptions often repeated in trademark doctrine: (1) that trademark owners are the sole authors of trademark value and (2) that consumers are mere passive recipients of information from marks. Literature from cognitive science, marketing and other social sciences is used to show the many ways in which consumers contribute to the success or failure of marks and actively use marks for expressive and informational purposes. By adopting this broadened view of consumer investment, trademark doctrine would take into account actual consumer interests. In Section III, the discussion identifies the type of return that consumers should receive so that trademark law can evolve on a principled path that preserves public interests. Because consumers invest marks with meaning and value, they should be able to use marks as tools for finding information. Section III suggests three contexts in which adopting the model of consumer investment could inform the choice to expand trademark protection or create a safe harbor: keyword advertising disputes, a safe harbor for dictionaries and other reference materials, and the use of marks that have been culturally diluted. Application of the consumer investment model to current trademark doctrine in these contexts and others would provide a means for assuring that actual consumers interests are heard in contexts that affect public access to information. Deborah R. Gerhardt University of North Carolina at Chapel Hill