PayPal president David Marcus has quit the eBay unit to run the mobile messaging business at Facebook.
Marcus will leave PayPal at the end of June, a little over two years after stepping up to the position of president. EBay president John Donahoe will take charge of PayPal until a new president is found.
Marcus arrived at PayPal in 2011 as head of mobile after the payments giant paid $240 million for Zong, the firm he founded in 2008 that enabled users to make online purchases for virtual goods using their mobile phones.
In a Facebook post, Marcus says that after the experience of managing a major company with thousands of employees, he has decided to return to "something that is closer to what I love to do every day", adding "I'm looking forward to getting my hands dirty again attempting to build something new and meaningful at scale".
In his newly created role, he will oversee the Messenger service within Facebook as well as the Messenger mobile app but not the recently-acquired WhatsApp.
Marcus's appointment will inevitably invite speculation about Facebook's interest in payments as it seeks to monitise its Messanger app, which is used by 200 million people a month but does not display ads.
Says a Facebook statement: "We're excited by the potential to continue developing great new messaging experiences that better serve the Facebook community and reach even more people, and David will be leading these efforts."