Uber Technologies Inc. reported weaker-than-expected fourth-quarter earnings and operating income, citing legal and regulatory expenses, and cautioned that currency headwinds would have an impact on first-quarter bookings.

Uber stock is lower Wednesday as the ride-hailing firm's soft first-quarter outlook offsets its strong fourth-quarter results. Here's what you need to know.

While net income jumped to $6.9 billion in the fourth quarter, Uber said this included a $6.4 billion benefit from a tax valuation release and a $556 million benefit due to net un