Ride-hailing app firm Uber saw its losses spiral by 61% to $4.5bn (£3.2bn) in 2017, up from $2.8bn in 2016 – despite an 85% increase in revenue to $37bn.
However, Uber’s loss of $1.1bn in the final quarter of the year was down 21% on the figure of $1.4bn in 2016.
Uber has been beset by problems, in particular the threat to close down its London operations.
Transport for London revoked Uber’s licence due to concerns over its vetting of drivers after claims of sexual assault by a number of female passengers. Uber is appealing the decision.
The company put the improved Q4 figures down to better control of costs such as advertising and customer support.
A company spokesman said: “We're incredibly encouraged by our financial performance and excited by our long-term potential to serve riders, drivers and cities.”
Uber recently won a $1.25bn investment from Japan’s SoftBank, which has acquired a 15% stake in the group.
New chief executive Dara Khosrowshahi says he hopes Uber will move into profit this year, with a stockmarket flotation (IPO) planned for 2019.