ToplineShares of top health insurance firms fell sharply in premarket trading Tuesday morning, after the Trump administration issued a proposal that would keep Medicare payment rates flat in 2027, falling short of Wall Street expectations.Centers for Medicare & Medicaid Services outlined a proposal to raise Medicare Advantage payment rates by only 0.09% in 2027.Copyright 2024 The Associated Press. All rights reserved.Key FactsIn premarket trading, UnitedHealth Group’s shares fell nearly 9% to $317.51, while ...