Chief financial officer David Wehner told analysts in a follow-up call to brace for a possibly deeper slowdown as the company seeks to expand new offerings such as Stories and increase privacy and security for users.
His fortune tumbled in late trading Wednesday, as shares of the social media giant slid 20% in post-market trading in NY on disappointing results. That figure includes some $2.7 billion in cash and real estate, according to Bloomberg's Billionaire index.
For the second quarter, the social network reported earnings-per-share of $1.74 on revenues of $13.23 billion, as well as 2.23 billion monthly active users. Revenue increased 42 percent to $13.2 billion, missing the $13.3 billion Wall Street consensus.
Facebook has been struggling for years with criticism about its content policies, its failure to safeguard private data and its changing rules for advertisers.
Facebook also had 185 million North American DAUs and 279 million European DAUs, below the FactSet forecasts of 185.4 million and 279.4 million respectively.
But the shedding is still notable because Facebook, until now, has only ever experienced growth in users quarter-to-quarter.
Even though Facebook's stock price had fallen nearly 10% in after-hours trading at one point due to a miss on revenue-albeit a narrow one-Chief Executive Mark Zuckerberg opened the call just after 5 p.m.
Best Amazon Prime Day Canada Deals (2018): Echo, Movies & More
Amazon said small and medium-sized businesses had sold more than $1 billion in since Monday, when the event started. As the number of Prime subscribers continues to grow, so to does that size and scale of Amazon's Prime Day sale .
The company remains in a dominant position in mobile advertising alongside Alphabet Inc's Google. Those problems hadn't mattered to the success of the business - until now.
Daily user growth for Facebook's namesake service has slid in six straight quarters, bringing it to 1.47 billion users in the second quarter from 1.23 billion at the end of 2016 when it became embroiled in political issues. Wehner said the drop was due entirely to a data protection and privacy law that took effect in Europe in May known as the General Data Protection Regulation, or GDPR.
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.
There's a scratch in Facebook's Teflon coating as the social networking company loses approximately US$150 billion ($219b) in market capitalisation in under two hours, Reuters has reported.
Still, the news caught analysts by surprise after 12 straight quarters in which Facebook exceeded analysts' expectations. The company owns three other properties with more than 1 billion users: WhatsApp, Messenger and Instagram.
Zuckerberg said Wednesday that he was hopeful Facebook would be able to limit disinformation and fake accounts, and that the company was able to do so in elections this year in France, Mexico and Germany. Given all the questions about the misuse of the platform, "to explain that there are a couple million people who chose not to continue using Facebook is unsurprising", said Brian Wieser, an analyst at Pivotal Research.
After-hours trade saw Facebook shares plunge by some 21 per cent, wiping out an estimated US$130 billion in market value if the slump is confirmed at Thursday's market opening.