The social media giant's shares dropped 20% - wiping over €100bn of its share price
Facebook has recorded the biggest fall in value in corporate history.
The social media giant’s value plunged by €102.91 ($120bn), when markets opened in New York today.
The 20% drop in share value came after Facebook warned that it is expecting weaker growth moving forward.
The warning, which came during a conference call for its second-quarter results after markets closed yesterday, sparked a share sell-off and drop of 24% in after-hours trading.
The company had warned investors to expect a surge in costs due to efforts needed to address concerns about the Cambridge Analytica scandal and Facebook's inadequate handling of users' privacy.
Facebook also said it expects slower user growth, partly due to the effect of the data privacy scandals.
The firm said it had 2.23 billion monthly active users at the end of June, up 11% on June 2017, marking the slowest growth in more than two years.
Total revenue for the quarter rose 42% to $13.23bn, but was below analysts' estimates of $13.36bn.
At the conference call chief financial officer David Wehner said operating profit margin will sink to the "mid-30s" for more than two years.
He added that quarterly revenue growth would be closer to 30% for the rest of the year, due to currency fluctuations and users choosing to have less personalised adverts as they opt out because of the European Union's General Data Protection Regulation (GDPR).
Shares in other technology companies were dragged down by the social media giant, as the technology sector fell 1.9%.
Chris Beauchamp, chief market analyst at IG Group said: "Perhaps the data scandal is at last beginning to bite in Facebook's earnings.
"Certainly, the frequent references to the other platforms available such as Instagram and the new revenue metric of how many people use at least one of the Facebook apps each month send a message that this is a company looking to find ways of becoming more than just a social media platform.
"High expectations can be a remarkable burden, and the reaction is often brutal when they are missed, but the revenue miss was slight, and $13.2 billion is not to be sniffed at.
"Facebook might have its wings clipped, but it is still a remarkable money-making machine."