Short answer: Premium tax credits are ACA subsidies that lower the monthly premium for marketplace coverage. They’re based on income and are available to people who don’t have an affordable, minimum-value offer of employer or government coverage.
Premium tax credits reduce what eligible enrollees pay for a qualified health plan purchased through the ACA marketplace. Eligibility is based on household income and the cost of the benchmark Silver plan, and the credit isn’t available to anyone with an affordable, minimum-value offer of employer coverage or access to other qualifying coverage. The credit can be taken in advance each month or claimed at tax time, and it’s reconciled on IRS Form 8962.