In the United States, Medicare is a federal social insurance program that provides health insurance to people over the age of 65, individuals who become totally and permanently disabled, end stage renal disease (ESRD) patients, and people with ALS. Recent research has found that the health trends of previously uninsured adults, especially those with chronic health problems, improves once they enter the Medicare program.[45] Traditional Medicare requires considerable cost-sharing, but ninety percent of Medicare enrollees have some kind of supplemental insurance—either employer-sponsored or retiree coverage, Medicaid, or a private Medigap plan—that covers some or all of their cost-sharing.[46] With supplemental insurance, Medicare ensures that its enrollees have predictable, affordable health care costs regardless of unforeseen illness or injury.
All U.S. citizens living in the United States are subject to the individual shared responsibility provision as are all permanent residents and all foreign nationals who are in the United States long enough during a calendar year to qualify as resident aliens for tax purposes. This category includes nonresident aliens who meet certain presence requirements and elect to be treated as resident aliens. For more information see Pub. 519. More: Shared Responsibility from the IRS (See Question 11)
Persistent lack of insurance among many working Americans continued to create pressure for a comprehensive national health insurance system. In the early 1970s, there was fierce debate between two alternative models for universal coverage. Senator Ted Kennedy proposed a universal single-payer system, while President Nixon countered with his own proposal based on mandates and incentives for employers to provide coverage while expanding publicly run coverage for low-wage workers and the unemployed. Compromise was never reached, and Nixon's resignation and a series of economic problems later in the decade diverted Congress's attention away from health reform.

Beginning with 10% of blue-collar workers in 1885, mandatory insurance has expanded; in 2009, insurance was made mandatory on all citizens, with private health insurance for the self-employed or above an income threshold.[23][24] As of 2016, 85% of the population is covered by the compulsory Statutory Health Insurance (SHI)[25] (Gesetzliche Krankenversicherung or GKV), with the remainder covered by private insurance (Private Krankenversicherung or PKV) Germany's health care system was 77% government-funded and 23% privately funded as of 2004.[26] While public health insurance contributions are based on the individual's income, private health insurance contributions are based on the individual's age and health condition.[23][27]

A 2011 study found that there were 2.1 million hospital stays for uninsured patients, accounting for 4.4% ($17.1 billion) of total aggregate inpatient hospital costs in the United States.[12] The costs of treating the uninsured must often be absorbed by providers as charity care, passed on to the insured via cost-shifting and higher health insurance premiums, or paid by taxpayers through higher taxes.[13]

California developed a solution to assist people across the state and is one of the few states to have an office devoted to giving people tips and resources to get the best care possible. California's Office of the Patient Advocate was established July 2000 to publish a yearly Health Care Quality Report Card[37] on the top HMOs, PPOs, and Medical Groups and to create and distribute helpful tips and resources to give Californians the tools needed to get the best care.[38]
In March 2017, the U.S. House of Representatives passed The Small Business Health Fairness Act (H.R. 1101), which established "requirements for creating a federally-certified AHP, including for certification itself, sponsors and boards of trustees, participation and coverage, nondiscrimination, contribution rates, and voluntary termination."[79][84]
The remaining 45% of health care funding comes from insurance premiums paid by the public, for which companies compete on price, though the variation between the various competing insurers is only about 5%.[citation needed] However, insurance companies are free to sell additional policies to provide coverage beyond the national minimum. These policies do not receive funding from the equalization pool, but cover additional treatments, such as dental procedures and physiotherapy, which are not paid for by the mandatory policy.[citation needed]
Public insurance cover increased from 2000–2010 in part because of an aging population and an economic downturn in the latter part of the decade. Funding for Medicaid and CHIP expanded significantly under the 2010 health reform bill.[9] The proportion of individuals covered by Medicaid increased from 10.5% in 2000 to 14.5% in 2010 and 20% in 2015. The proportion covered by Medicare increased from 13.5% in 2000 to 15.9% in 2010, then decreased to 14% in 2015.[3][10]