(Telecompaper) Kevin Turner, the former Walmart executive who has led Microsoft's sales team for the past 11 years, is leaving the software giant to become CEO of trading firm Citadel Securities. Turner held the title of Chief Operating Officer at Microsoft, but his role was more that of sales chief. Microsoft said he would leave the software maker "after a short transition period". According to a memo from Microsoft CEO Satya Nadella to employees, the company plans to split Turner's responsibilities among five different executives.