UnitedHealth Stock Is a Big Drag on the Dow

The Dow Jones Industrial Average looked set to open in the red Tuesday after one of its 30 components named a new CEO and suspended its guidance.

The blue-chip index was on track to open down 140 points. UnitedHealth stock, down 10% in premarket trading, was on track to shave 214 points off the Dow, putting the index in negative territory on its own. UnitedHealth closed Monday with a stock price of $380.64, making it one of the largest members the Dow because the index weighs its components by stock price, rather than market cap.

The health insurer said Tuesday that Stephen J. Hemsley would take over as CEO, with Andrew Witty stepping down from the role for "personal reasons," and pulled its full-year outlook, citing higher-than-expected medical expenditures.