Attention to the asset value of intellectual property (IP) has traditionally concentrated on high‐value patent sales and licenses. This narrow focus neglects nonpatent assets held by a broader set of economic agents, such as trademarks, and overlooks the evolving ways owners are employing and monetizing their intangible assets. To help remedy this deficiency, the Office of Chief Economist of the United States Patent and Trademark Office (USPTO) is releasing a series of datasets in formats convenient for researchers. This article describes the USPTO Trademark Assignment Dataset, a database of over 785,000 transactions recorded during 1952–2013 affecting almost 4.2 million trademark registrations and applications. We provide a comprehensive description and present key trends, showing that among registrations issued during 1978–2013, more than 31% were affected by some transaction during their lives, 21% were transferred to different parties, and 12% were involved in at least one security interest agreement. Examining transaction rates by registration cohort, we find evidence that registered U.S. trademarks may be more likely to be traded than are U.S. patents. Other trends and findings are discussed. Despite limitations, these data open new avenues for research, particularly with respect to trademark collateralization and the market for brands.