Facebook Inc. (FB - Get Report) shares fell on Wednesday following a report that suggested CEO Mark Zuckerberg was aware of privacy issues at the social media giant linked to the Cambridge Analytica data scandal.

The Wall Street Journal said emails, which were unearthed by Facebook as part of the ongoing Federal Trade Commission investigation, showed that Zuckerberg was aware of some problematic issues related privacy concerns. Cambridge Analytica's use of tens of millions of Facebook users' data -- without their consent -- to potentially meddle with political movements around the world, including the U.S. Presidential election in 2016, has led to an FTC investigation. In its most recent quarterly report, Facebook indicated it had set aside $5 billion for fines from the FTC linked to violating its 2012 consent order on data privacy. 

"We have fully cooperated with the FTC's investigation to date and provided tens of thousands of documents, emails and files. We are continuing to work with them and hope to bring this matter to an appropriate resolution," Facebook responded to the Wall Street Journal. "Facebook and its executives, including Mark, at all times strive to comply with all applicable law, and at no point did Mark or any other Facebook employee knowingly violate the company's obligations under the FTC consent order."

Facebook shares fell 2.2% by late afternoon trading Wednesday to change hands at $174.16 each following publication of the Wall Street Journal piece, a move that trims its year-to-date gain to around 32%.

The Cambridge Analytica case involved a political consulting firm funded by right-wing contributors, including Trump adviser Steve Bannon, and hired by the Trump presidential campaign. The company gained access to personal data of 50 million Facebook users as a way to gain information to be used to influence voting patterns.

The New York Times reported last month that one of the sticking points in the talks between Facebook and the FTC is to what extent Zuckerberg should be held personally liable for the infractions.

The multi-billion-dollar fine would be among the largest ever imposed by the FTC, and the largest ever levied against a major tech firm. In 2012, the agency slapped a $22.5 million on Google for allegedly tricking Apple (AAPL - Get Report) Safari users into letting Google track their web activity. More recently, the agency fined the app Musical.ly, now known as TikTok, $5.7 million for failing to obtain proper parental consent in collecting the personal information of minors. It fined Verizon's (VZ - Get Report) Oath $5 million for a similar offense late last year.