• Established “health exchanges” or “marketplaces” on a statewide basis that sold community-rated individual and family insurance policies that were required to cover ten sets of “essential health benefits.” Policies could be sold in four “metal tiers”, Bronze, Silver, Gold, and Platinum, which cover 60%, 70%, 80%, and 90%, respectively, of typical health expenses. The tiers with the more comprehensive coverage generally have higher premiums.
•Provided income-based subsidies to purchase insurance policies on the exchanges. Families earning up to four times the FPL were eligible for at least some financial assistance to pay for insurance. Various restrictions applied; for example, people with access to employer-sponsored health insurance, and those with incomes below the U.S. poverty level, could not purchase on the exchanges.
• Provided coverage free of cost-sharing requirements for specific services (e.g., annual physicals, some screenings) and for poorer Americans.
• Required that insurers sell coverage to applicants regardless of health status (called “guarantee issue”)
• Liberalized Medicaid coverage so that (as passed originally) everyone up to 138% of the FPL (except legal immigrants, who may have to wait five years before obtaining coverage)  would be eligible for Medicaid, regardless of their family circumstances. In 2012 the U.S. Supreme Court ruled that requiring states to expand their Medicaid was unconstitutional. Nineteen states have chosen not to expand Medicaid even though 90% of costs were to be paid for by the federal government.
• Required that most people have health insurance or pay a penalty, a provision called the “individual mandate.” Employers with more than 50 employees were also required to provide coverage or pay a penalty although implementation of this provision was delayed.
• Required that employers that provide family coverage to workers cover workers’ children until the reach the age of 26.
Source: Thomas Rice, Lynn Y. Unruh, Ewout van Ginneken, Pauline Rosenau, Andrew J. Barnes, Universal coverage reforms in the USA: From Obamacare through Trump, Health Policy, Volume 122, Issue 7, 2018, Pages 698-702, ISSN 0168-8510, https://doi.org/10.1016/j.healthpol.2018.05.007. http://www.sciencedirect.com/science/article/pii/S0168851018301544