New federal tax credits were authorized in the Patient Protection and Affordable Care Act (ACA, P.L. 111-148, as amended), to help certain individuals pay for health insurance coverage, beginning in 2014. ACA requires "American Health Benefit Exchanges" to be established in every state by January 1, 2014, either by the state itself or by the Secretary of Health and Human Services (HHS). Exchanges will not be insurers, but will provide eligible individuals and small businesses with access to private health insurance plans. Generally, the plans offered through the exchanges will provide comprehensive coverage and meet all ACA market reforms, as applicable. One of the requirements that most exchange plans must meet is to provide a certain level of coverage generosity based on actuarial value. Each level of coverage generosity is designated according to a precious metal and corresponds to a specific actuarial value: Bronze (actuarial value of 60%), Silver (70%), Gold (80%), and Platinum (90%). To make exchange coverage more affordable, certain individuals will receive premium assistance in the form of federal tax credits. The premium credit will be an advanceable, refundable tax credit, meaning taxpayers need not wait until the end of the tax year in order to benefit from the credit, and may claim the full credit amount even if they have little or no federal income tax liability. Although the premium credits will not be available until 2014, the illustrations provided in this report are based on current federal poverty levels, to reflect how the estimated premium credit amounts compare to current income levels. Under ACA, the amount received in premium credits is based on income tax returns. These amounts are reconciled in the next year and can result in overpayment of premium credits if income increases, which must be repaid to the federal government. ACA limited the amount of required repayments. Since the enactment of ACA, these limits have been increased in order to raise revenues for other legislative initiatives (e.g., P.L. 111-309 and P.L. 112-9). Most recently, on June 7, 2012, the House passed H.R. 436, the Health Care Cost Reduction Act of 2012, which includes a measure that would remove all limits on repayment, making individuals fully liable for the full amount of any premium credit overpayment. Relative affordability of health insurance premiums individuals and families might face within health insurance exchanges will likely vary from exchange to exchange based on a host of factors, including enrollees' age, the varying prices paid by plans for medical goods and services, the breadth of the provider network, the provisions regarding how out-of-network care is paid for (or not), and the use of tools by the plan to reduce health care utilization (e.g., prior authorization for certain tests). Examples provided in the Appendix of this report depict a range by which premiums might reasonably be expected to vary based on enrollees' age, and variation in medical costs across geographic areas, for purposes of illustration only. Actual premiums will likely vary among health insurance exchanges based on a wide range of factors other than those depicted in this report.