Instagram co-founders Kevin Systrom and Mike Krieger are leaving Facebook Inc., according to a report from the New York Times Monday.

Although neither gave an overt reason for leaving in their resignation letters, Chief Executive Systrom said in a statement that he and Chief Technology Officer Krieger (pictured) were “planning on taking some time off to explore our curiosity and creativity again.”

Suggesting that they may be planning on a new startup, Systrom added that “building new things requires that we step back, understand what inspires us and match that with what the world needs; that’s what we plan to do.”

The pair departs Instagram eight years after founding the app, which they sold only two years later to Facebook for $1 billion. Although the acquisition was controversial at the time, Instagram has been remarkably successful for Facebook. It was valued at $100 billion in June after passing 1 billion users and an estimated $10 billion in annual revenue.

The move follows in the steps of Jan Koum, co-founder and chief executive of Facebook-owned messaging giant WhatsApp, who quit Facebook in April over disagreements over data privacy, advertising and encryption.

Even as Systrom provided an official explanation for his and Krieger’s departure, that hasn’t stopped speculation that the timing may be the result of other issues.

Business Insider noted that the resignations come “following months of turmoil and scandals for Facebook, from Cambridge Analytica’s misappropriation of tens of millions of Facebook users’ data to sustained fallout from the spread of Russian propaganda during the 2016 election.”

Nonetheless, Instagram’s future inside Facebook still looks bright. “This in itself doesn’t yield any great need for concern,” Yuval Ben-Itzhak, CEO of social media and digital marketing firm Socialbakers, said in an email. “Since Facebook acquired Instagram in 2012 the platform has gone from strength to strength. We certainly don’t see the platform’s growth slowing any time soon.”

Whatever the reason, both Krieger and Systrom are both well-set financially to do whatever they please. And with the amazing success of Instagram behind them, Sand Hill Road venture capitalists will be lining up to invest in whatever project or startup they decide to build in the future.

Photo: jdlasica/Flickr