Is There A Risk Hiding In Uber Stock's Best-Looking Number?

Over the past twelve months, Uber Technologies (UBER) converted 12.1% of its revenue into operating profit. That performance marks the highest margin in five years. While the figure appears encouraging on the surface, shareholders have reason to worry that the margin slips from here. The business was still running an operating loss just three years ago. So what pushed Uber's margin this high, and can it stay there.