David M. Anderson

More than 16 million people receive health care coverage through the Affordable Care Act’s (ACA) individual health insurance marketplaces. Many enrollees receive premium subsidies that are tied to the premium of the second least expensive silver plan available. This study investigates the consistency of the least expensive silver plan offered on Healthcare.gov from 2014 to 2021 and finds that on average, from one year to the next, the same insurer offered the least expensive silver plan in 63.1% of counties representing 54.7% of the population. However, even when the same insurer offers the least expensive plan, almost half the time, they introduce a new, less expensive plan in the next policy year. Consequently, ACA enrollees who previously purchased the least expensive silver plan may face incremental premium costs unless they spend time and effort to carefully reevaluate their choices each year. We estimate the potential premium cost of inattention and show how it varies over time and across states.