Affordable Care Act (ACA) Marketplace enrollment increased following the enactment of enhanced premium tax credits in 2021, as more individuals became eligible for subsidies. In 2025, individual market enrollment reached a record high of 25.2 million people. However, it is not yet known how many ACA enrollees effectuated coverage, so the size of the on- and off-exchange market remains uncertain. In 2024, the effectuation rate was 96.9%. If that rate holds steady, approximately 23.6 million people would have enrolled in coverage through the exchanges in 2025, with an estimated 1.6 million enrolled off-exchange. (Note: The aforementioned effectuation rate and estimates of on and off-exchange enrollment for 2025 were corrected on June 18, 2025).