Twitter has a serious growth problem.

Trigger-happy investors know this as well, because the company's stock has tanked in after-hours trading today, following the release of its fourth quarter earnings. Here's what is happening: Twitter reported its Q4 earnings Wednesday, and it revealed that no new users were added since last quarter. Twitter has 320 million total users, the same number it reported in Q3.

Analysts had forecasted a bump of 3 million new users. But the story gets worse. Active users dropped during the 90-day period. Only 305 million users were active on Twitter per month on average, whereas the company reported 307 million active users in Q3 of 2015. Due to news of poor user growth, Twitter's stock is down roughly 12 per cent in after hours trading.

As far as the financial stuff goes, Twitter met Wall Street’s expectations by reporting profits of 16 cents per share on revenue of $710 million in Q4, meaning it experienced a revenue spike of 48 per cent.

Tune into Twitter's investor call at 5 pm EST to hear from company executives.