Funding from the equalization pool is distributed to insurance companies for each person they insure under the required policy. However, high-risk individuals get more from the pool, and low-income persons and children under 18 have their insurance paid for entirely. Because of this, insurance companies no longer find insuring high risk individuals an unappealing proposition, avoiding the potential problem of adverse selection.
The US has a joint federal and state system for regulating insurance, with the federal government ceding primary responsibility to the states under the McCarran-Ferguson Act. States regulate the content of health insurance policies and often require coverage of specific types of medical services or health care providers. State mandates generally do not apply to the health plans offered by large employers, because of the preemption clause of the Employee Retirement Income Security Act.
Most provider markets (especially hospitals) are also highly concentrated—roughly 80%, according to criteria established by the FTC and Department of Justice—so insurers usually have little choice about which providers to include in their networks, and consequently little leverage to control the prices they pay. Large insurers frequently negotiate most-favored nation clauses with providers, agreeing to raise rates significantly while guaranteeing that providers will charge other insurers higher rates.
Historically, health insurance has been regulated by the states, consistent with the McCarran-Ferguson Act. Details for what health insurance could be sold were up to the states, with a variety of laws and regulations. Model acts and regulations promulgated by the National Association of Insurance Commissioners (NAIC) provide some degree of uniformity state to state. These models do not have the force of law and have no effect unless they are adopted by a state. They are, however, used as guides by most states, and some states adopt them with little or no change.
Health insurance can be tricky to navigate. Managed care insurance plans require policyholders to receive care from a network of designated health care providers for the highest level of coverage. If patients seek care outside the network, they must pay a higher percentage of the cost. In some cases, the insurance company may even refuse payment outright for services obtained out of network. Many managed care plans require patients to choose a primary care physician who oversees the patient's care and makes recommendations about treatment. Insurance companies may also deny coverage for services that were obtained without preauthorization. In addition, insurers may refuse payment for name-brand drugs if a generic version or comparable medication is available at a lower cost.
Health insurance in the United States is any program that helps pay for medical expenses, whether through privately purchased insurance, social insurance, or a social welfare program funded by the government. Synonyms for this usage include "health coverage", "health care coverage", and "health benefits". In a more technical sense, the term "health insurance" is used to describe any form of insurance providing protection against the costs of medical services. This usage includes private insurance and social insurance programs such as Medicare, which pools resources and spreads the financial risk associated with major medical expenses across the entire population to protect everyone, as well as social welfare programs like Medicaid and the Children's Health Insurance Program, which both provide assistance to people who cannot afford health coverage.