Facebook shares plunged Wednesday evening after the tech giant failed to meet Wall Street's estimates for user growth and quarterly revenue.

The disappointing results come after Facebook has been embroiled in a data scandal affecting millions of users - an event that the firm's top leadership acknowledged as a factor weighing on user growth during the second quarter.

Shares of Facebook dipped more than 20% to $173.73 in after-hours trading on Wednesday. The stock has risen about 23.2% so far this year.

By Wednesday evening, almost $150 billion had been wiped off of Facebook's market cap as a result of the stock's plunge.

Meanwhile, Facebook CEO Mark Zuckerberg saw his net worth dive roughly $18.8 billion to $63.6 billion. At the closing bell on Wednesday, Zuckerberg was worth $82.4 billion, according to Forbes.

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The Cambridge Analytica scandal prompted several apologies from CEO Mark Zuckerberg (pictured) and generated calls for users to desert Facebook, which has grown strongly since launching as a public company in 2012

FACEBOOK EARNINGS IN FIGURES Daily active users (DAUs) – DAUs were 1.47 billion on average for June 2018, an increase of 11% year-over-year. Monthly active users (MAUs) – MAUs were 2.23 billion as of June 30, 2018, an increase of 11% year-over-year. Mobile advertising revenue – Mobile advertising revenue represented approximately 91% of advertising revenue for the second quarter of 2018, up from approximately 87% of advertising revenue in the second quarter of 2017. Capital expenditures – Capital expenditures for the second quarter of 2018 were $3.46 billion. Cash and cash equivalents and marketable securities – Cash and cash equivalents and marketable securities were $42.31 billion at the end of the second quarter of 2018. Headcount – Headcount was 30,275 as of June 30, 2018, an increase of 47% year-over-year. Advertisement

Total monthly active users came in at 2.23 billion, which fell short of analysts' estimated 2.25 billion.

Users in Europe dropped from 377 million to 376 million, partly as a result of the new General Data Protection Regulation rules.

Facebook executives made investors even more nervous when they warned of further revenue deceleration in a call with analysts.

CFO David Wehner said Facebook expects to see high-single digit drops in year-over-year revenue growth during the next few quarters.

He cited the new GDPR rules, user privacy controls and currency headwinds as factors contributing to the deceleration.

Wehner reiterated that GDPR didn't have a significant impact on revenues because it was implemented toward the tail-end of the quarter, but he said that could change in the coming quarters.

'We do think there will be a modest impact and I don't want to overplay these factors,' Wehner said in a call with analysts.

'...We're continuing to focus our privacy model around putting privacy first. We believe that will have some impact on revenue growth.

'It's really a combination of how we're approaching privacy and GDPR and the like. All those factors together are...[things] we're considering.'

The Cambridge Analytica scandal prompted several apologies from Zuckerberg and generated calls for users to desert Facebook, which has grown strongly since launching as a public company in 2012.

Ad sales in the second quarter rose 42 percent to $13.04 billion but costs, bolstered by moves to improve content and security after the data scandal, rose 50 percent from a year earlier to $7.37 billion.

Shares of Facebook dipped more than 20% to $173.73 in after-hours trading on Wednesday. Almost $150 billion was wiped off of Facebook's market cap as a result of the stock's plunge

Facebook lost some customers in Europe after the stringent General Data Protection Regulation (GDPR) came into affect. Facebook execs called it a 'modest' drop in users

Total revenue rose 41.9 percent to $13.23 billion, while Wall Street was looking for revenue of $13.36 billion.

Ahead of the announcement, industry experts had predicted that the number of active users visiting the social network would either drop, or flat line.

Facebook has never reported anything other than user growth in Europe.

Still, Zuckerberg assured investors that Facebook continues to see growth on its core platform, as well as its other properties, which include Instagram, WhatsApp and Messenger.

For the first time ever, Zuckerberg provided user growth data on those properties, saying that Facebook now has 2.5 billion people who use at least one of its apps, referring to users who may have an Instagram account, as well as a Facebook profile.

'Our community and business continue to grow quickly,' said Mark Zuckerberg.

'We are committed to investing to keep people safe and secure, and to keep building meaningful new ways to help people connect.'

DAUs were 1.47 billion on average for June 2018, an increase of 11% year-over-year. Meanwhile, users in Europe dropped from 377 million to 376 million, partly as a result of the new General Data Protection Regulation rules

Monthly active users came in at 2.23 billion, which fell short of analysts' estimated 2.25 billion

According to analysts, stalling numbers are likely the result of forcing Facebook users to consciously opt-in to having their information used for personal advertising – one of the key stipulations of the stringent GDPR rules.

This quarter is a crucial period of time for the Menlo Park-based social network as it incorporates both the enforcement of GDPR in Europe, and the fall out from the Cambridge Analytica scandal, which saw the data of 87 million users mined by a political data firm without their knowledge.

GDPR, which came into affect May 25, stipulates that companies must explicitly request consent from their users in order to personal data for advertising purposes.

Companies that do not comply with GDPR can be fined up to four per cent of their global revenue.

To comply with the new regulations, Facebook rolled-out a security check-up to users worldwide which asked them to review what kind of personal information they consent to sharing for advertising targeting.

Users were also asked to consent to facial recognition technology on the site.

Analysts believe users may have been scared off by the explicit details about how their data is being used by the social network.

Facebook last month confirmed the number of North American users had dipped for the first time.

Wedbush Securities managing director Michael Pachter told the Telegraph: 'European monthly active users grew sequentially over the last four quarters to end at 377 million.

'We estimate zero sequential growth for June, ending again at 377 million.'

Analysis by high-street bank Barclays has also revealed Facebook has 20 million European users under the age of 16. Under GDPR, these children now have to obtain parental consent in order to remain on the platform.

'We expect some drop off, similar to other companies like Twitter and Snapchat from the kids issue,' Barclays said.

To comply with the new regulations, Facebook rolled-out a security check-up to users worldwide which asked them to review what kind of personal information they consent to sharing for advertising targeting

WHAT CHANGES IS FACEBOOK MAKING TO COMPLY WITH THE EU'S GENERAL DATA PROTECTION REGULATION? The European Union's General Data Protection Regulation (GDPR) will enter into force on May 25, 2018 and offer greater privacy protection online. New terms of service at Facebook are designed to ensure the Menlo Park, California, firm complies with the forthcoming EU rules, with European residents seeing the measures first. Facebook is hoping to exclude 1.5 billion of its worldwide users from the new GDPR laws, arguing that only EU citizens should fall under its purview. Almost 1.9 billion non-EU international users, outside of the US and Canada, would be protected by the stricter law under current rules. Members in Africa, Asia, Australia and Latin America would be excluded from the GDPR's protections if the move goes ahead. Under the new policy, Facebook users will be asked to review and make choices about ads they receive, including whether they want Facebook to use data from third parties. Facebook will begin to ask users if they want to opt in or out of its facial recognition feature, which is making a return under GDPR. They will also be asked to review and choose what to share about sensitive personal data. This will include their political and religious beliefs, as well as relationship status information on their profiles. Facebook is also taking steps to comply with rules that limit advertising and public viewing of data for teens. This will mean no use of facial recognition for anyone under age 18 and limitations on who can see certain information teens have shared. To comply with GDPR, Facebook will also limit what it shows to users between the ages of 13 and 15 unless they get permission from a parent. Advertisement

Advertising revenue is not expected to be affected despite the drop in users.

A lower number of DAUs (daily active users) would have a minimal effect on advertising revenue, said chief strategy officer and head of technology research for GBH Insights, Daniel Ives.

The analytical firm predicts a worst-case scenario of a two per cent drop in annual advertising revenue – around £760 million ($1 billion).

eMarketer principal analyst, Debra Aho Williamson, believes North American DAUs will follow last month's trend and be down or flat.

Ms Williamson does however, expect European DAUs to be lower for the first time, but she claims it may be irrelevant in the long run.

'Even if MAU (monthly active users) and DAU show some weakness, Facebook has done an excellent job of becoming an indispensable communications platform,' Ms Williamson told CNBC.

'Simply put, it's very hard to leave Facebook entirely.

'Perhaps people will share less often or become more careful about what they share, but we believe that it remains a very important platform for many people.

'And we also believe that engagement trends on Instagram as well as Messenger and WhatsApp will remain strong.'

Facebook itself may be facing tough times, but its empire is thriving.

Last month, Instagram announced it had hit one billion monthly users and analysts expect Facebook to post around £10.1 billion ($13.3 billion) in revenue, up 43 per cent from 2017.