Shares of several big-name health care companies plunged after the Trump administration proposed nearly flat rates for Medicare Advantage insurers.The proposal entails a net average payment increase of 0.09% for Medicare Advantage plans in 2027, according to a release from the Centers for Medicare and Medicaid Services on Monday. That number is significantly less than Wall Street analysts' expectations that the agency would propose a rate increase of between 4% to 6% for next year. CMS typically finalizes M ...