Shares in Twitter are set to fall when Wall Street opens after it reported that its fourth-quarter losses had nearly doubled.
The social networking service reported a loss of $167m (£133m) in the final three months of 2016, as against $90m in the same period a year earlier.
Average active user numbers came in at 319 million for the quarter, 4% up on a year earlier.
Fourth-quarter revenues were $717m, 1% up on last year’s $710m.
It was the company’s slowest quarterly revenue growth since it became a publicly listed company in November 2013.
Analysis: Rory Cellan-Jones, technology correspondent
These were supposed to be the results that showed Twitter resurgent after a year of disappointment. The fact that it had been the prime social networking battleground during the US election and that every tweet from the new president garnered worldwide attention would have new brought new users – and advertisers – flocking in.
That was the theory. In fact, the figures showed the slowest growth in quarterly revenue in the company’s short history and a very modest increase in user numbers. The company has put on a brave face, focusing on the growth in daily rather than monthly active users.
It also says that revenue growth is lagging user growth – but investors have grown impatient for evidence that Twitter has found a sustainable business model.
Donald Trump’s tweets – and the reactions they provoke – may have become essential viewing for journalists and the markets. Whether they make Twitter a great destination for advertisers is a different matter.
Revenues and user numbers both fell short of analysts’ expectations.
Despite the increased losses, Twitter chief executive Jack Dorsey said 2016 had been “a transformative year” for the service.
“We reset and focused on why people use Twitter: it’s the fastest way to see what’s happening and what everyone’s talking about,” he said.
“We overcame the toughest challenge for any consumer service at scale by reversing declining audience trends and re-accelerating usage.”
He said daily active usage had risen for the third consecutive quarter and the upward trend was set to continue.
“While revenue growth continues to lag audience growth, we are applying the same focused approach that drove audience growth to our revenue product portfolio, focusing on our strengths and the real-time nature of our service.
“This will take time, but we’re moving fast to show results.”