- Insiders told CNBC that Chris Cox was the "heart and soul" of Facebook.
- His departure hangs uncertainty on Facebook's recent announcement to integrate its family of apps and prioritize private communication.
- Separately Friday, Facebook drew criticism related to a terrorist incident in New Zealand in which a shooter live-streamed his attack on Facebook.
Facebook stock fell Friday, the day after Chief Product Officer Chris Cox announced he was leaving the company in light of its recent pivot to privacy.
Shares fell as much as 4.5 percent in early trading, sinking below $163 at its lowest point. The stock eased off by mid-morning and ended the day 2.5 percent down.
Insiders told CNBC that Cox was the "heart and soul" of Facebook. He was among the earlier employees and reported directly to CEO Mark Zuckerberg. His departure hangs uncertainty on Facebook's recent announcement to integrate its family of apps and prioritize private communication.
Separately Friday, Facebook drew criticism related to a terrorist incident in New Zealand in which a shooter live-streamed his attack on Facebook. The shootings claimed at least 49 lives.
The company was alerted to the post by New Zealand police and said it has been taking down re-postings of the video and messages praising the shooter as it becomes aware of them.
On top of that, Facebook suffered its longest outage ever this week. The service was reinstated Thursday after a widespread outage that last nearly a day.
In a statement Thursday, the company blamed a "server configuration change that triggered a cascading series of issues" for the outage.
The stock shed 1.8 percent by the end of trading Thursday.
Friday's stock losses cap a rough week for the company.
A proposal by Massachusetts Senator and presidential candidate Elizabeth Warren to break up big tech continued to garner headlines and raise concern in the investor community. Warren's proposal would see Facebook divesting its major acquisitions, WhatsApp and Instagram.
The risk to many of the so-called FAANG stocks — Facebook, Apple, Amazon, Netflix and Google — led one analyst to favor Netflix by sheer default.
Meanwhile, federal prosecutors are probing Facebook's data-sharing partnerships with device makers, according to a report by the New York Times published Wednesday night.
"It has already been reported that there are ongoing federal investigations, including by the Department of Justice," a spokesperson for Facebook said in a statement to CNBC. "We are cooperating with investigators and take those probes seriously. We've provided public testimony, answered questions, and pledged that we will continue to do so."