According to estimates from ad measuring firm, Standard Media Index, Facebook, which is the world’s second-largest seller of online ads after Google, was losing around $545,000 in U.S. ad income per hour during the outage.

On Monday, Facebook’s shares plummeted after the business experienced its biggest network outage in more than a decade, and a day after “60 Minutes” aired an interview with a whistleblower accusing the firm of abandoning democracy.

The Nasdaq Composite, which is heavily weighted in technology, was down nearly 2% on Monday. The drop was most severe among social media stocks, with Twitter, Snap, and Pinterest all falling more than 5%. At the time of writing the article, Facebook shares slid 4.9% to close at $326.23. The stock is still up 19.43% this year. However, as Facebook comes back online, we can see a positive move for the future market as Facebook is up +0.34%.

What really happened? 

Facebook’s main app, as well as its Instagram and WhatsApp services, went down shortly before noon ET. As of market closure, they were still unavailable.

“We’re aware that some people are having trouble accessing our apps and products,” the company said in a tweet. “We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience.”

The outage is Facebook’s worst since a glitch knocked the company’s services offline for approximately a day in 2008, affecting over 80 million users. The company presently has a user base of 3 billion people.

Frances Haugen worked as a product manager for Facebook’s civic misinformation unit before leaving the company in May after stealing a huge amount of internal files. According to Haugen, Facebook emphasizes “personal profits over public safety – putting people’s lives in peril.”

Haugen revealed herself as the whistleblower who disclosed important internal business documents to the Wall Street Journal. In an interview with “60 Minutes”, the information was used in a series of recent investigations named “The Facebook Files” by The Wall Street Journal.