Twitter reported Wednesday that the number of active users in the most recent quarter was flat compared to the previous quarter. That's the first time it hasn't seen sequential user growth since it went public in 2013.
The stock, which closed at $14.98 US in regular market trading, fell after-hours following the company's release of its quarterly financial results.
Twitter said it had an average of 320 million monthly active users in the fourth quarter, the same as in the previous quarter.
Excluding those who access Twitter through messaging platforms, it reported 305 million monthly active users, a decline of two million from the third quarter.
The company said it lost $90.2 million US, though revenues rose 48.3 per cent to $710.5 million US in the quarter ended Dec. 31, roughly in line with market expectations.
But its first-quarter revenue guidance came in below what analysts were forecasting.
"We are going to fix the broken windows and confusing parts" of the service, Twitter wrote in a note released along with the fourth-quarter report.
Twitter co-founder Jack Dorsey returned as CEO last summer, promising to re-ignite growth in the social networking firm.
The stock has plunged almost 70 per cent in the last year as investors worry about the company's slowing growth in its user base.
Tweaking the feed
Twitter's financial results came on the same day it unveiled a major change to the way it displays users' tweets.
Until now, Twitter has displayed tweets in reverse chronological order, with the most recent tweets displayed at the top.
Under its new system, Twitter will use a complicated sorting system to give priority placement to tweets that the company considers most relevant or important to its users. That's similar to how Facebook operates.
Users will initially have the option of turning on the new sorting algorithm by going into their settings and choosing "Show me the best tweets first."
But eventually, Twitter will automatically convert all its 320 million users' timelines to the new system. Users will always have the option of turning it off and going back to the traditional, most-recent-first display.