Brutal week.

Facebook Inc. (FB - Get Report) shares edged higher at the opening bell Friday even as the tumult surrounding the world's biggest social group shows no signs of abating following a data scandal that may have breached the privacy of 50 million users.

Facebook has lost more than $50 billion in market value this week, with shares slumping more than 10% over the past five days as the fallout from the Cambridge Analytica scandal, which saw the controversial political consultancy improperly obtain user data that it may have used to help sway the 2016 elections in favor of President Donald Trump, continued to escalate.

"We know this is an issue of trust. We know this is a critical moment for our company, for the service we provide," COO Sherly Sandberg told CNBC television late Thursday. "We are going to do everything we can."

Action Alerts Plus holding Facebook shares were marked 1.1% higher in early trading Friday to change hands at $166.72, a move that would trim its five-day slump to 10% and hive more than 16.1% from the all-time high it reached on Feb. 2.

Sandberg's appearance followed several days of silence from the company's senior executives that was only broken Wednesday by a series of media mea culpas from CEO Mark Zuckerberg, who apologized for the "breach of trust" and suggested he would be willing to testify before lawmakers and accept tougher regulation from government officials to protect user data.

Watch TheStreet's latest analysis on Facebook below.

"Mark has said, 'It's not a question of if regulation, it's a question of what type,'" explained Sandberg. "We're open to regulation. We work with lawmakers all over the world."

Lawmakers on both sides of the Atlantic are keen to take the billionaire Facebook founder and his most-trusted colleague at their word, with both Republican Greg Walden and Democrat Frank Pallone saying Thursday that they will ask Zuckerberg to appear before the House Energy and Commerce Committee that the two co-chair.

"The latest revelations regarding Facebook's use and security of user data raises many serious consumer protection concerns," the Committee said in a statement. "After committee staff received a briefing yesterday from Facebook officials, we felt that many questions were left unanswered."

In Britain, where Cambridge Analytica is based, MP  Matt Hancock, the country's Minister for Digital, Culture, Media and Sport, told BBC radio that "it shouldn't be for a company to decide what is the appropriate balance between privacy and innovation and use of data. Those rules should be set by society as a whole and so by Parliament."

The spectre of tighter regulation for data-dependent social media and tech firms has taken its toll on shares this week, and again Friday, with Netflix Inc. (NFLX - Get Report) marked 1.7% at $301.5, the lowest since March 5, and Twitter Inc. (TWTR - Get Report) trading 1.28% lower at $30.80 each, a move that would take its five-day decline to 13.4%.