MCO meaning in Healthcare ?

The term managed care or managed healthcare is used in the United States to describe a group of activities intended to reduce the cost of providing health care and providing American health insurance while improving the quality of that care ("managed care techniques"). It has become the essentially exclusive system of delivering and receiving American health care since its implementation in the early 1980s, and has been largely unaffected by the Affordable Care Act of 2010.

...intended to reduce unnecessary health care costs through a variety of mechanisms, including: economic incentives for physicians and patients to select less costly forms of care; programs for reviewing the medical necessity of specific services; increased beneficiary cost sharing; controls on inpatient admissions and lengths of stay; the establishment of cost-sharing incentives for outpatient surgery; selective contracting with health care providers; and the intensive management of high-cost health care cases. The programs may be provided in a variety of settings, such as Health Maintenance Organizations and Preferred Provider Organizations.

The growth of managed care in the U.S. was spurred by the enactment of the Health Maintenance Organization Act of 1973. While managed care techniques were pioneered by health maintenance organizations, they are now used by a variety of private health benefit programs. Managed care is now nearly ubiquitous in the U.S, but has attracted controversy because it has had mixed results in its overall goal of controlling medical costs. Proponents and critics are also sharply divided on managed care's overall impact on U.S. health care delivery, which ranks among the best in terms of quality but among the worst with regard to access, efficiency, and equity in the developed world.