Since 2014, millions of individuals have purchased coverage through the health insurance exchanges established under Patient Protection and Affordable Care Act (PPACA). PPACA altered the individual health insurance market by setting federal standards for coverage and subsidizing exchange coverage for certain low-income individuals. In the first 5 years of exchanges, issuers have moved in and out of the market and increased premiums, but little is known about issuers' claims costs or the factors driving their business decisions. Chapter 1 examines (1) claims costs of issuers participating in...