The Dow drops as Nvidia stock slides again and UnitedHealth tanks -- but it's not all red / UnitedHealth's stock drops over 22% for worst day since 1998. Here's why / Stocks making the biggest moves midday: Eli Lilly, Alphabet, Hertz, UnitedHealth and more / UnitedHealth's stock is plunging on higher medical costs. That may mean trouble for more insurers / Stocks making the biggest moves premarket: Hertz, UnitedHealth, Eli Lilly and more / UnitedHealth shares tank on steep forecast cut as medical care costs soar / Stock Movers: UnitedHealth, Eli Lilly, Netflix.com / UnitedHealth shares plunge 22% after insurer slashes profit forecast / S&P 500 rises as investors claw back losses; Dow drops 400 points on UnitedHealth plunge: Live updates / UnitedHealth Shares Plummet as Too Many People Go to the Doctor