Abstract: The market for patient data has never been more active. Technology companies, from startups to giants, are eager to access electronic health record (EHR) data to build the next generation of health-focused products. Medical artificial intelligence (AI) is particularly data-hungry; large, representative data sets hold promise for advancing not only AI companies’ growth, but also the health of patients. Companies’ overtures to major hospitals about data sharing have highlighted legal and ethical uncertainties as to whether and how to undertake these relationships. One such partnership is now being challenged in court. In June 2019, a patient sued the University of Chicago Medical Center and Google for alleged misuse of patient EHR data. This Viewpoint discusses the case and what it signals about the need for thoughtful governance of data sharing between health care organizations and technology companies.