CSX drops in premarket as CEO takes medical leave

Shares of CSX are tumbling in premarket trading Friday following the railroad company's announcement that its CEO will take a medical leave.

CSX Corp. says Hunter Harrison is on leave "due to unexpected complications from a recent illness." Operating Chief James Foote will serve as acting CEO of the Jacksonville, Florida-based company.

Harrison, who's led turnarounds at three other railroads, was hired in March after the Mantle Ridge hedge fund pressured CSX to make changes. But questions have emerged about his health. In May The Wall Street Journal reported that Harrison often works from home and occasionally uses oxygen because of an undisclosed health issue. Harrison then told the newspaper that doctors had cleared him to work.

CSX's stock slid more than 12 percent to $50.34 before the market open.