With yet another volatile week for the stock market in December in the books, the week was packed with interesting news. But three stories in tech -- one from Amazon.com (NASDAQ:AMZN) and two from Facebook (NASDAQ:FB) -- stood out.

  1. Amazon shared some upbeat news about its holiday sales.
  2. Facebook CEO Mark Zuckerberg shared an update on the company's progress with addressing safety concerns.
  3. Citron Research made a bullish call on Facebook stock.
Facebook CEO Mark Zuckerberg presents 10-year plan at F8 conference in 2016

Facebook CEO Mark Zuckerberg. Image source: Facebook.

Amazon's record holiday

On Wednesday, Amazon said it wrapped up another record-breaking holiday season, with "more items ordered worldwide than ever before." 

The press release featured a number of notable updates on the company's holiday season, including the following:

  • Amazon sold millions more Amazon-branded devices than in the same time last year.
  • Over 1 billion items were shipped free of shipping charges this holiday season to members with Prime memberships.
  • Three times as many orders were made through Alexa this year than last year.
  • Tens of millions of people signed up for Prime memberships.

This update bodes well for Amazon's fourth quarter, which includes the holiday season. Management had guided for sales during the fourth quarter to rise 10% to 20% year over year. 

Facebook's safety update

In a Facebook post on Friday, CEO Mark Zuckerberg gave an overview of his thoughts on the company's recent progress to address safety concerns on the platform. 

The CEO's focus in 2018 has been on issues such as "preventing election interference, stopping the spread of hate speech and misinformation, making sure people have control of their information, and ensuring our services improve people's well-being," Zuckerberg said. "In each of these areas, I'm proud of the progress we've made."

More specific updates included the fact that Facebook now has over 30,000 people working on safety, that it's spending "billions of dollars in security yearly," and that it's removing millions of fake accounts every day.

But Zuckerberg acknowledged that addressing safety concerns is "more than a one-year challenge."

Facebook stock: Headed to $160?

Another interesting story on Facebook during the week was Citron Research's bullish call on the social network's stock. Setting a 12-month price target of $160, Citron argued that the stock has become undervalued after being beaten down amid heightened scrutiny of Facebook's platform security and safety.

Facebook stock has fallen nearly 40% since July, giving the stock a price-to-earnings ratio of 20. This drop has given the stock a conservative valuation relative to its earnings potential.

"Facebook is growing faster than 95% of the [stocks in the] S&P, with margins higher than about 90% of the S&P," Citron said in its note on the stock. "However, for the first time, Facebook is trading at a discount to the S&P and is at its lowest multiple ever."

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Daniel Sparks owns shares of Amazon. The Motley Fool owns shares of and recommends Amazon and Facebook. The Motley Fool has a disclosure policy.