One of Facebook’s top executives and a close adviser to CEO Mark Zuckerberg is leaving the company, Zuckerberg said on Thursday.

Chris Cox has been Facebook’s chief product officer since 2014, a job that most recently gave him oversight of all of the company’s apps including Facebook and Instagram, and has been at the social networking company for more than a decade.

“For a few years, Chris has been discussing with me his desire to do something else,” Zuckerberg said in a memo posted on a company website.

The memo did not say what Cox would do next, and it did not name someone to take on the full range of Cox’s responsibilities.

Another Facebook executive, the chief of messaging service WhatsApp, will also leave the company, according to the memo. Chris Daniels became the head of the service less than a year ago in a management shake-up after Jan Koum, one of WhatsApp’s co-founders, said he would leave.

Facebook posted Zuckerberg’s memo as the stock market was closing for the day. Shares fell 2 percent in after-hours trading.