San Francisco (AFP) – Facebook shares plunged as much as 22 percent Wednesday after the world’s biggest social network reported weaker-than-expected user growth, suggesting a series of scandals on data privacy may impact growth.

Shares tumbled in after-hours exchanges after the disappointing quarterly report brought an abrupt end to Facebook’s run to record highs.

The financial results were close to expectations, but a weak outlook appeared to spook the market. Profit was up 31 percent in the second quarter at $5.1 billion; revenues rose 42 percent to $13.2 billion, slightly below most forecasts.

Chief executive Mark Zuckerberg said the tech giant has been investing heavily in “safety, security and privacy” after being rocked by concerns of manipulation of the platform and the hijacking of user data.

“We’re investing so much in security that it will start to impact our profitability, we’re starting to see that this quarter,” Zuckerberg told a conference call on quarterly results.

But he added that “we run this company for the long term, not for the next quarter.”

Zuckerberg has said he did not expect a meaningful impact from the uproar over data hijacked by political consulting firm Cambridge Analytica, but the last quarter’s figures suggested some cooling.

Chief financial officer David Wehner said revenue growth “decelerated” in the second quarter and will decline “by high single digit percentages” and added that “we are also giving people who use our services more choices around data privacy which may have an impact on our revenue growth.”

– User decline in Europe –

The key metric of monthly active users rose 11 percent to 2.23 billion, below most estimates of 2.25 billion, while daily active users grew a weaker-than-expected 11 percent to 1.47 billion.

Zuckerberg said Facebook lost around one million users in Europe amid the implementation of new EU data protection rules, but noted that many Europeans “want to use context from ads,” suggesting they are opting into allowing data collection for advertising purposes.

Almost all of Facebook’s revenue — $13 billion of the total $13.2 billion — came from online advertising, a sector dominated by the California social network along with Silicon Valley rival Google.

Although Facebook shares were in a slump after the Cambridge Analytica scandal broke earlier this year, the stock had risen sharply and hit record levels this month.

According to the research firm eMarketer, Facebook is expected to hold an 18 percent share of the $273.29 billion worldwide digital ad market, behind Google’s 31 percent.

According to the research firm, Facebook-owned Instagram is making up for some of the slowdown in growth at the social network and will generate $8.06 billion in worldwide ad revenue this year.