Much has been written about the Affordable Care Act (ACA) in the 5 years since its inception, both in scholarly journals and the popular press. Initial interest focused on states’ decisions about whether to implement their own insurance marketplaces and accept Medicaid expansion.1 There were countless accounts of dismal enrollment experiences marred by technical glitches during the initial enrollment period in late 2013 and early 2014.1 With implementation issues settled by the Supreme Court, and state and federal websites much improved, attention has recently turned to the operational aspects of the insurance markets. In particular, concerns have been increasing about the often limited hospital and physician networks offered by insurance plans sold in the marketplaces.2,3