The association’s offers opened 20% down, a drop that wiped more than $100bn (£76bn) off Facebook’s fairly estimated worth.
The fall additionally hauled down the tech-rich Nasdaq share record, which was just about 1% lower.
Facebook’s gauge came as the firm faces a reaction over its treatment of phoney news and client information.
The organization said it anticipated that would support spending by half or more, as it uses to enhance the way it screens content, tracks sponsors and treats client information – zones where it has confronted controller examination.
The firm additionally cautioned speculators that income development would be harmed as individuals to make utilization of new alternatives to confine promoting and less productive abroad markets drive development.
Facebook, which likewise claims Instagram and WhatsApp, said its edges would therapist to the mid-30% territory, from around 44% in the latest quarter.
The worries, in spite of Facebook’s year-on-year income development of over 40% in the latest quarter, seemed to taint some other innovation stocks.
Twitter, which has confronted comparable feedback to Facebook and is because of report quarterly outcomes to financial specialists on Friday, was down around 3%, as was Snap, the social informing administration.
Different organizations demonstrated stronger.
Letter set, which possesses Google and YouTube, and furthermore depends on advanced publicizing, was down under 1%, while music spilling administration Spotify picked up right around 1%, subsequent to announcing more grounded than anticipated client development.
A large number of the components influencing Facebook are remarkable to the organization, said Daniel Ives, boss innovation officer at GBH Insights.
The firm has been in the spotlight for its association with information firm Cambridge Analytica.
Facebook has likewise changed the news source to underscore posts from family and companions, changes that CEO Mark Zuckerberg had beforehand forewarned would influence productivity.
Investigator Richard Greenfield of BTIG Research wrote in a note that financial specialists were “overcompensating”.
He said Facebook remained a rich open door for promoters, and the speculations it is making should drive long haul development.
“We were really worried amid Facebook’s Q2 2018 telephone call and could detect the dread/freeze in financial specialists voices subsequently,” he composed.
In any case, he included: “Versatile is eating the world and Facebook is a centre holding to profit by that move.”