Affordable Care Act (ACA) enhanced premium tax credits are set to expire at the end of this year. The enhanced tax credits both increased the amount of financial assistance already eligible ACA Marketplace enrollees received as well as made middle-income enrollees with income above 400% of federal poverty guidelines eligible for premium tax credits. Since the introduction of the enhanced premium tax credits, enrollment in the Marketplace has more than doubled from about 11m to over 24m people, the vast majority of whom receive an enhanced premium tax credit. If enhanced tax credits expire, many Marketplace enrollees will continue to qualify for a smaller tax credit, while others will lose eligibility altogether and be hit by a "double whammy" of losing their entire tax credit and being on the hook for rising premiums. For many Americans, their premiums will double.