WhatsApp co-founder to exit Facebook

The co-founder of messaging service WhatsApp, Jan Koum, announced Monday that he is leaving the platform's parent company Facebook.

WhatsApp was purchased by Facebook in 2014 for $19 billion. The popular service was developed in 2009 by Koum and Brian Acton, who left Facebook last year and has recently criticized WhatsApp's owner as a reckless abuser of user data.

According to a report in the Washington Post, Koum left Facebook over disputes regarding the company's use of user data, but his official statement did not reveal his feelings about the issue.

"It's been almost a decade since Brian and I started WhatsApp, and it's been an amazing journey with some of the best people," Koum wrote on a Facebook post. "But it is time for me to move on. I've been blessed to work with such an incredibly small team and see how a crazy amount of focus can produce an app used by so many people all over the world."

Koum did not reveal when exactly he would depart the company.

Facebook chief executive Mark Zuckerberg replied to Koum's post and said he respected his decision.

"I will miss working so closely with you," Zuckerberg wrote. "I'm grateful for everything you've done to help connect the world, and for everything you've taught me, including about encryption and its ability to take power from centralized systems and put it back in people's hands. Those values will always be at the heart of WhatsApp."

Facebook's handling of user data has been at the heart of a scandal in recent months after it became widely publicized that political consultancy firm Cambridge Analytica was able to access the personal data of millions of Americans without their express permission.

Facebook shares were slightly lower Monday amid the news and closed down 1 percent at $172.