WhatsApp co-founder Jan Koum is leaving parent company Facebook Inc. , according to a report in the Washington Post late Monday. Koum is departing Facebook after fighting with company executives over the messaging service’s strategy, and Facebook’s attempt to use WhatsApp personal data and weaken its encryption, according to anonymous sources cited by the Post. Koum sold WhatsApp to Facebook in 2014 for more than $19 billion. Koum co-founded WhatsApp with Brian Acton, who left Facebook in 2017. Koum plans to step down from Facebook’s board and the date of his departure isn’t known, according to the Post. Koum confirmed his departure in a Facebook post after the Post published its story. Facebook stock was flat in after-hours trading. The stock closed down less than 1% to $172. Facebook stock has fallen 8% in the past three months, as the S&P 500 index has dropped 5.4%.