Over a million Americans dropped health insurance after enhanced premium subsidies expired, mostly young and healthy individuals. This led to higher premiums as insurers cover sicker enrollees, causing a cycle known as an adverse selection death spiral. Similar market collapses occurred in the 1990s without mandates. The Affordable Care Act's subsidies and mandate helped prevent this nationally, but with weakened protections, insurers propose double-digit premium hikes for 2027, risking further market instability.