Piacentini was also one of the largest employee shareholders at Amazon. Before he left in 2016, he owned the third largest number of Amazon shares among all employees, after only Bezos and the retail group's CEO, Jeff Wilke, according to the company's 2017 proxy statement. The 79,146 shares he owned at the time would translate to roughly $122 million based on Monday's closing price.
Piacentini previously hinted that he could come back to Amazon once his pro bono work with the Italian government was complete. In an interview with the Financial Times in September 2017, he said he planned to return to the e-commerce company, although he noted that "many things can change." During a Bloomberg interview this year, he declined to say whether he's returning to Amazon.
It's unclear what his future plans are now. He didn't respond to a request for comment. Amazon declined to comment for this story.
Piacentini joins a growing list of executives who have left Amazon this year, even as the company enjoys unprecedented success and a near-record stock price. At least 15 high-profile executives have announced their departures this year, an unusually high number for a company known for retaining its most senior executives for many years.
Piacentini's departure is particularly notable given that he's the second S-Team member to leave Amazon this year, after Sebastian Gunningham, marketplace senior vice president, left in March. Bezos' S-Team, which reportedly contains fewer than 20 execs, is famous for seeing very little turnover historically, a part of Amazon's culture that the CEO once highlighted during an internal staff meeting.
"I'm very happy that we don't have a lot of turnover on the S-team," Bezos said, according to a recording of a 2017 all-hands meeting that CNBC has heard. "I don't intend to change that — I like you guys a lot. I would expect any transition there to happen very incrementally over a long period of time."