Facebook just had the biggest wipeout in stock market history.
Facebook has struggled in recent years with several privacy issues.
On the Q2 earnings call, CFO David Wehner said the company expects revenue growth to slow to single digits over the next two quarters from 42% year-over-year in the second quarter.
In a research note, he said Facebook´s outlook "suggests that while the company is still growing at a fast clip, the days of 30 percent-plus growth are numbered".
New European privacy rules, inspired in part by Facebook's relentless mining of its own users' data, are starting to hamper the company's advertising business.
It's the second time this year that Facebook's stock has taken a dramatic plunge.
Facebook has no end in sight for scrutiny and oversight, with regulators, prosecutors, and other public and private parties in multiple countries examining the company's actions, those of nation states allegedly manipulating news and advertising, and that of firms like Cambridge Analytica, which obtained massive amounts of information that many Facebook users likely considered private.
In the wake of the Cambridge Analytica data-privacy scandal, "Legal/regulatory developments have led to changes meant to support FB's platform and users, but they will notably restrain growth and profits for at least the next couple of quarters, in our opinion", Scott Kessler of CFRA Research wrote in a note.
CEO Mark Zuckerberg said that Facebook's profitability will be affected as it looks to invest more in security and privacy.
Facebook founder and current centre of controversy, Mark Zuckerberg, seemed unfazed by the loss of users.
Facebook's shares were at a record high before the figures were released.
Like this story? Share it with a friend! The company did manage to squeeze more money out of each person, with the all-important Average Revenue per User (ARPU) increasing to $5.97. But the number of American users who use Facebook every month has flatlined, the company reported, raising questions about how much longer the social network can continue to expand in the US market. All users had to affirm consent to its data collection practices before being allowed to continue to use Facebook. "GDPR is an added head wind, albeit containable", he said.
But the slowdown in growth has spooked investors.
Bloomberg reported Zuckerberg's fortune tumbled 17 percent in the first five minutes of trading Thursday.
A 3D-printed Facebook logo is seen in front of displayed stock graph in this illustration photo, March 20, 2018.