Before the development of medical expense insurance, patients were expected to pay all other health care costs out of their own pockets, under what is known as the fee-for-service business model. During the middle to late 20th century, traditional disability insurance evolved into modern health insurance programs. Today, most comprehensive private health insurance programs cover the cost of routine, preventive, and emergency health care procedures, and also most prescription drugs, but this was not always the case. The rise of private insurance was accompanied by the gradual expansion of public insurance programs for those who could not acquire coverage through the market.
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. 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.
However, in a 2007 analysis, the Employee Benefit Research Institute concluded that the availability of employment-based health benefits for active workers in the US is stable. The "take-up rate," or percentage of eligible workers participating in employer-sponsored plans, has fallen somewhat, but not sharply. EBRI interviewed employers for the study, and found that others might follow if a major employer discontinued health benefits. Effective by January 1, 2014, the Patient Protection and Affordable Care Act will impose a $2000 per employee tax penalty on employers with over 50 employees who do not offer health insurance to their full-time workers. (In 2008, over 95% of employers with at least 50 employees offered health insurance.) On the other hand, public policy changes could also result in a reduction in employer support for employment-based health benefits.
Health insurance companies are not actually providing traditional insurance, which involves the pooling of risk, because the vast majority of purchasers actually do face the harms that they are "insuring" against. Instead, as Edward Beiser and Jacob Appel have separately argued, health insurers are better thought of as low-risk money managers who pocket the interest on what are really long-term healthcare savings accounts.
In July 2009, Save Flexible Spending Plans, a national grassroots advocacy organization, was formed to protect against the restricted use of FSAs in health care reform efforts, Save Flexible Spending Accounts is sponsored by the Employers Council on Flexible Compensation (ECFC), a non-profit organization "dedicated to the maintenance and expansion of the private employee benefits on a tax-advantaged basis". ECFC members include companies such as WageWorks Inc., a benefits provider based in San Mateo, California.
However, with the Patient Protection and Affordable Care Act, effective since 2014, federal laws have created some uniformity in partnership with the existing state-based system. Insurers are prohibited from discriminating against or charging higher rates for individuals based on pre-existing medical conditions and must offer a standard set of coverage.
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. 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.