Shares in Twitter have fallen more than 10% after the company 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.
There were 319 million active users, 4% up on a year earlier, but revenue from ads fell slightly to $638m.
Donald Trump’s ardent use of Twitter did little to boost users or ad income.
Fourth-quarter revenues were $717m, 1% up on last year’s $710m.
Revenues and user numbers both fell short of analysts’ expectations.
It was the company’s slowest quarterly revenue growth since it became a publicly listed company in November 2013.
Some analysts had expected new US President Donald Trump’s widely publicised use of Twitter would give the service a financial boost.
But during a conference call, chief operating officer Anthony Noto dismissed the idea that the “Trump effect” had been a key factor in user growth.
He said that while Mr Trump had shown “the power of Twitter” and broadened awareness of the service, it was hard for “an event or a single person” to make such a difference.