Facebook stock price down 5% amid global outage

US social network company Facebook saw its stock price plummet more than 5% on Monday after its services, including Instagram and WhatsApp, have all gone down globally for hours.

Facebook's stock price was trading at $325 per share at 3.55 p.m. EDT shortly before the closing bell on the Nasdaq -- down 5.25% from the previous close of $343.01 a share on Friday, according to official figures.

The company's market value lost around $50.7 billion, standing at $915.1 billion at the time, down from $965.8 billion on Friday

Facebook co-founder and CEO Mark Zuckerberg saw his net worth decline $6.1 billion, or 5%, to $116.5 billion on Monday, according to Forbes' Real-Time Billionaires List where he stands at 6th place.

Facebook, Instagram and WhatsApp saw outages earlier worldwide according to the DownDetector website that tracks internet service outages.

Nearly 124,000 outages have been reported on Facebook, almost 97,000 on Instagram, and more than 33,000 on WhatsApp, according to latest data on DownDetector.

"We're aware that some people are having trouble accessing our apps and products," Facebook spokesman Andy Stone said on Twitter. "We're working to get things back to normal as quickly as possible, and we apologize for any inconvenience."

WhatsApp said on Twitter it is "aware that some people are experiencing issues with" the application "at the moment".

"We're working to get things back to normal and will send an update here as soon as possible. Thanks for your patience!" said the company.

The outage's cause remains unclear.