Roughly one year after WhatsApp co-founder Brian Acton made his highly publicized exit from Facebook, another executive and early employee of the messaging platform is doing the same. Neeraj Arora, WhatsApp’s chief business officer, announced today that he would be “taking some time off to recharge and spend time with family.”

Facebook acquired WhatsApp for $19 billion in 2014 and pledged to allow the messaging giant to continue to operate independently under Acton and co-founder Jan Koum, who served as its chief executive officer until abruptly quitting over privacy and data concerns in April. Arora, who joined WhatsApp in 2011 from Google, was rumored to be the frontrunner to replace Koum as CEO. With him out the door, it’s unclear who will be tapped to lead WhatsApp.

In today’s announcement, Arora said he was “deeply indebted” to both Acton and Koum, “who entrusted me to be their business companion for so many years.”

Facebook subsidiaries WhatsApp and Instagram are both in periods of flux following the exits of their original founders, which are believed to be caused by quarrels with the social media giant’s CEO Mark Zuckerberg .

In what was one of the largest tech stories of 2018, Instagram co-founders Kevin Systrom and Mike Krieger announced they were leaving Facebook years after the company acquired their photo-sharing app for $1 billion. They shared the news in September, just a few months after Koum stepped down from WhatsApp.

According to The New York Times, Zuckerberg, over the course of the last year, had begun to assert more and more control over Instagram, upsetting its leaders.

According to TechCrunch’s Josh Constine, Koum, for his part, was unhappy “about how Facebook would monetize his app and the impact of that on privacy.” Both Acton and Koum departed Facebook before they fully vested from the multi-billion acquisition, meaning the pair chose to lose hundreds of millions of dollars over continued employment at Facebook.