FORTUNE -- As health insurance is reshaped, some major corporations are switching the way they offer coverage to current employees and retirees, in a move that is likely to pave the way for major change to the American health care system. IBM -- which has about 110,000 retirees -- is planning to shift its traditional company-administered plan to private Medicare health insurance exchanges for people who are 65 and older. Retirees can use company subsidies to buy Medicare Advantage plans or other coverage to supplement the services they receive under the federal program.
