During the trading day, the price went as low as $172 at 9:40 am on Thursday, as investors continued to trade shares. "As of Wednesday, Facebook Inc., lost over $100 billion in stock market value".
For Mark Zuckerberg, it's just about a fifth of his net worth. The company's sales grew at a 42% clip in the second quarter, so the forecast implies that its growth rate for the rest of the year will be 35% or less. An executive also warned it expects revenue growth to slow down in the next couple of quarters.
Meanwhile, Facebook is also still coming to terms with the European Union's new privacy laws and the impact the rules will have on the business.
Growth in the number of users who logged in each day fell short, too, up 11 percent year-over-year at 1.47 billion but still less than the 1.49 billion anticipated.
The unwanted media attention Facebook received for its part in the Cambridge Analytica data sharing scandal has spilled into the platform's dissemination of fake news, and Zuckerberg felt compelled to apologize for his company's lack of professionalism and failure to maintain consumer confidence.
Facebook has shown that it can not sail forever forward while facing various storms, including Cambridge Analytica and the Russian government's use of the social media platform to sow divisions amongst Americans during the 2016 presidential campaign. But perhaps most damaging of all, the company warned of a growth slowdown.
The slump is the biggest drop in market capitalisation in history - far exceeding Intel's $91bn single-day loss in September 2000.
Instagram is its parent company's fastest-growing slice of revenue, but it touts 4 million fewer monthly advertisers globally.
Revenue increased 4% to $13.2 billion in the quarter.
Describing the announcements as "bombshells", Baird analysts said the issues were to a large degree "self-inflicted" as Facebook sacrifices its core app monetisation to drive usage. Analysts projected $13.3 billion.
"The company has a track record of resetting revenue growth and expense expectations only to turn around and exceed those expectations the following quarter", Munster wrote.
"We think that's the right thing to do for the business", he said. Facebook's stock price now stands at $176.26, having dropped by a massive 18.9% from the $217.50 value that it stood at before the company's earnings call.
While privacy was an issue in Europe, politics played a role in North America, which is the company's most lucrative advertising market.
Greenfield said he could "sense the fear/panic in investors' voices" after the Facebook analyst call, but that he had maintained his outlook.