Health-insurance stocks are plummeting on the White House's proposal to hold Medicare rates flat for a year

TIMOTHY A. CLARY / AFP via Getty Images

• Health insurers saw shares plunge on Tuesday on the latest proposals for Medicare.
• The Trump administration proposed holding Medicare Advantage payments roughly flat in 2027.
• UnitedHealth CEO says the proposed payment rate will lead to "very meaningful benefit reductions."

Health-insurance stocks plunged on Tuesday amid the latest updates from the White House on Medicare plan payments for next year.

Major insurers...