Uber Technologies last night posted a wider third-quarter loss as the company tries to outspend competitors through discounts and invests heavily in loss-making new business ventures.

The figures sent its shares down 5.5% in after-hours trading on Wall Street. 

Nevertheless, the company promised it would be profitable by the end of 2021 as quarterly revenues, driven by its global ride-hailing business, beat expectations. 

Uber's chief executive Dara Khosrowshahi said that the company as a whole would achieve adjusted EBITDA profitability for the full year of 2021.

But he declined to provide details on the performance of individual business units by that time. 

The move follows a similar announcement by smaller ride-hailing competitor Lyft last week. 

Uber's costs jumped about 33% to $4.92 billion in the latest quarter. Gross bookings, which include ride-hailing, mobility, food delivery and freight payments, rose 29% from a year earlier to $16.47 billion. 

Overall, the company's net loss widened to $1.16 billion in the quarter ended September 30, from $986m a year earlier, while net loss on a per-share basis narrowed to 68 cents from $2.21. 

Known for its ride-hailing app available in more than 700 cities worldwide, Uber has vastly diversified its business over the past years. 

The company is building out its long-haul trucking and food delivery business Uber Eats, developing self-driving cars, offering banking services to its drivers and even planning commercial passenger drone shuttles by 2023. 

It collected total third-quarter revenues of $3.81 billion, up nearly 30% year over year, beating estimates of $3.69 billion. 

But Uber is facing regulatory challenges to its business model and shareholders so far appear unimpressed by the company's push to diversify. 

Its shares have lost some 30% since going public in May as investors lose patience with venture capital-fueled startups offering only murky paths to profitability. 

Shares are expected to be squeezed further on Wednesday, when a restriction on selling stock lifts. 

Some analysts expect more than 80% of the company's outstanding shares will become eligible for sale. 

With Uber under pressure, investors are keen to see the company expanding market share. 

Uber's monthly active users across rides, bike shares and food delivery rose to 103 million globally in the third quarter, from 82 million a year earlier. But they fell short of analysts' estimates of 105.5 million, according to IBES data from Refinitiv.

Last night's results also heightened the differences between Uber and Lyft, which only operates in the US and Canada.  

Lyft executives on Wednesday, in an apparent dig at Uber's sprawling business ventures, emphasised they remained squarely focused on mobility. 

Revenue from Uber's ride-hailing business rose about 19% to $2.90 billion and contributed $631m to third-quarter earnings. 

Sales from Uber Eats, the company's fastest-growing unit, rose 64%, but nearly 40% of revenues were spent on incentive and referral payments, as Uber tries to gain market share. 

Uber hopes its ride-hailing business will come in handy, allowing the company to undercut competitors' delivery costs by having drivers ferry around pizzas instead of passengers when demand is low. 

In doing so, Uber, like other "gig economy" businesses, is largely relying on freelance contractors. 

A new California law, set to go into effect on January 1, would turn most of the state's roughly 450,000 gig workers into full-time employees and has garnered nationwide attention. 

Uber, Lyft and food delivery company DoorDash have pushed for separate legislation that would increase pay and benefits for drivers yet maintain their status as independent contractors. 

Khosrowshahi said he was hoping US politicians would be willing to work with the industry. 

"But if not, we'll continue to aggressively defend our drivers' right to flexibility," the CEO said.