Fitbit warns, leaves investors in bad shape

Fitbit (FIT), a maker of activity trackers, is tanking in after-hours trading after issuing a disappointing outlook that has now cost investors who bought the stock early half their money.

Shares of the maker of devices to analyze personal activity are down 16% in after-hours trading to $13.87 apiece after the company said its expects revenue in the first quarter to be between $420 million and $440 million. Analysts are looking for revenue for the quarter $486 million, says S&P Global Market Intelligence. Shares closed Monday up 92 cents, or 5.9%, to $16.48.