Recent cancellations of nongroup health insurance plans generated much policy debate and raised concerns that the Affordable Care Act (ACA) may increase the number of uninsured Americans in the short term. This article provides evidence on the stability of nongroup coverage using US census data for the period 2008–11, before ACA provisions took effect. The principal findings are threefold. First, this market was characterized by high turnover: Only 42 percent of people with nongroup coverage at the outset of the study period retained that coverage after twelve months. Second, 80 percent of people experiencing coverage changes acquired other insurance within a year, most commonly from an employer. Third, turnover varied across groups, with stable coverage more common for whites and self-employed people than for other groups. Turnover was particularly high among adults ages 19–35, with only 21 percent of young adults retaining continuous nongroup coverage for two years. Given estimates from 2012 that 10.8 million people were covered in this market, these results suggest that 6.2 million people leave nongroup coverage annually. This suggests that the nongroup market was characterized by frequent disruptions in coverage before the ACA and that the effects of the recent cancellations are not necessarily out of the norm. These results can serve as a useful pre-ACA baseline with which to evaluate the law’s long-term impact on the stability of nongroup coverage.