The US health insurance market is highly concentrated, as leading insurers have carried out over 400 mergers from the mid-1990s to the mid-2000s (decade). In 2000, the two largest health insurers (Aetna and UnitedHealth Group) had total membership of 32 million. By 2006 the top two insurers, WellPoint (now Anthem) and UnitedHealth, had total membership of 67 million. The two companies together had more than 36% of the national market for commercial health insurance. The AMA has said that it "has long been concerned about the impact of consolidated markets on patient care." A 2007 AMA study found that in 299 of the 313 markets surveyed, one health plan accounted for at least 30% of the combined health maintenance organization (HMO)/preferred provider organization (PPO) market. In 90% of markets, the largest insurer controls at least 30% of the market, and the largest insurer controls more than 50% of the market in 54% of metropolitan areas. The US Department of Justice has recognized this percentage of market control as conferring substantial monopsony power in the relations between insurer and physicians.
The Commonwealth Fund, in its annual survey, "Mirror, Mirror on the Wall", compares the performance of the health care systems in Australia, New Zealand, the United Kingdom, Germany, Canada and the U.S. Its 2007 study found that, although the U.S. system is the most expensive, it consistently under-performs compared to the other countries. One difference between the U.S. and the other countries in the study is that the U.S. is the only country without universal health insurance coverage.
Employer-sponsored health insurance plans dramatically expanded as a direct result of wage controls imposed by the federal government during World War II. The labor market was tight because of the increased demand for goods and decreased supply of workers during the war. Federally imposed wage and price controls prohibited manufacturers and other employers from raising wages enough to attract workers. When the War Labor Board declared that fringe benefits, such as sick leave and health insurance, did not count as wages for the purpose of wage controls, employers responded with significantly increased offers of fringe benefits, especially health care coverage, to attract workers.
Most aspects of private health insurance in Australia are regulated by the Private Health Insurance Act 2007. Complaints and reporting of the private health industry is carried out by an independent government agency, the Private Health Insurance Ombudsman. The ombudsman publishes an annual report that outlines the number and nature of complaints per health fund compared to their market share 
Health insurance is a type of insurance coverage that pays for medical and surgical expenses incurred by the insured. Health insurance can reimburse the insured for expenses incurred from illness or injury, or pay the care provider directly. It is often included in employer benefit packages as a means of enticing quality employees. The cost of health insurance premiums is deductible to the payer, and the benefits received are tax-free.
Deductible: The amount that the insured must pay out-of-pocket before the health insurer pays its share. For example, policy-holders might have to pay a $500 deductible per year, before any of their health care is covered by the health insurer. It may take several doctor's visits or prescription refills before the insured person reaches the deductible and the insurance company starts to pay for care. Furthermore, most policies do not apply co-pays for doctor's visits or prescriptions against your deductible.
Supporters of a public plan, such as Washington Post columnist E. J. Dionne, argue that many places in the United States have monopolies in which one company, or a small set of companies, control the local market for health insurance. Economist and New York Times columnist Paul Krugman also wrote that local insurance monopolies exist in many of the smaller states, accusing those who oppose the idea of a public insurance plan as defenders of local monopolies. He also argued that traditional ideas of beneficial market competition do not apply to the insurance industry given that insurers mainly compete by risk selection, claiming that "[t]he most successful companies are those that do the best job of denying coverage to those who need it most."
The proportion of non-elderly individuals with employer-sponsored cover fell from 66% in 2000 to 56% in 2010, then stabilized following the passage of the Affordable Care Act. Employees who worked part-time (less than 30 hours a week) were less likely to be offered coverage by their employer than were employees who worked full-time (21% vs. 72%).