Currently, its stocks are at US$174.89 down 0.78 per cent.
According to the complainant, the marketplace was "shocked" when "the truth" began to emerge on Wednesday from the Menlo Park, California-based company.
Those numbers are not just for its main Facebook site, but also across apps like Instagram and Whatsapp which are expected to have been behind the majority of the company's user growth.
During a routine call with analysts, Facebook's chief financial officer, David Wehner, startled brokerages by claiming the company faced a multi-year financial squeeze in the near future.
The lawsuit is designed for class-action status and seeks unspecified damages.
Giuliani says Trump could soon decide on Mueller interview
One of the tapes, which first aired on CNN this week, discusses a secret payment made to former playboy model Karen McDougal. But Davis said the president's team "forfeited all confidentiality" when Giuliani talked publicly last week about the tape.
Facebook's decline significantly outpaced the $91 billion that Intel lost in September of 2000, during the original dot-com bust.
Facebook said in its earnings report last week that it anticipated slower revenue growth and slimmer margins in the future, in part to improve the safety and privacy of the platform. Most of its large institutional investors aren't panicking. Since then, many have been consolidated in the federal court in San Francisco.
Thursday's plunge also hit Mr Zuckerberg's bottom line.
For numerous world's richest people, most especially Africa's billionaires, losing $16.8 billion in a day would be a wipeout.
Buffett now ranks third among the world's billionaires, while Zuckerberg is sixth. Shares of the social media behemoth fell 19 percent on Wednesday after the company reported second-quarter. This was due to issues involving fake news, trolls, and even Russian manipulators.
For more than a year already, Facebook and other social media companies have been under fire courtesy of policy makers and regulators.