Key Microsoft exec Kevin Turner departs, kicks off management shuffle

Microsoft is losing one of its most tenured leaders.

Chief Operating Officer Kevin Turner will become CEO of financial firm Citadel Securities, Microsoft CEO Satya Nadella said in an email to employees Thursday.

Turner's planned departure kicked off a few other management changes that reorganize sales for the tech giant. Judson Althoff will lead worldwide commercial business, and Jean-Philippe Courtois will head up global sales, marketing and operations. Both will report to Nadella.

The management moves mark the latest changes under Nadella, who took the reins from Steve Ballmer in 2014. Under Nadella, Microsoft has focused more on cloud services and pushing software on a subscription basis. The company promoted Terry Myerson to run the devices business and ejected former Nokia CEO Stephen Elop. Most shockingly, Satya decided to offer Windows 10 as a free upgrade, eschewing Microsoft's previous model of making customers pay for the software.

Nadella's even writing a book that chronicles the changes Microsoft's undergone recently.

Turner, meanwhile, has been with Microsoft since 2005, while Ballmer was still CEO. In the email, Nadella said Turner "built the sales force into the strategic asset it is today" while doubling the company's revenue.

While at Microsoft, Turner led more than 51,000 employees in 191 countries.

Before joining Microsoft, Turner spent about 20 years at Walmart. He was the chief information officer and later became CEO of Sam's Club. He will stay through the end of July to help with the transition.

"Kevin is a proven innovator who brings expertise in technology and operations with a client-first focus. I'm confident that under Kevin's leadership we will further distinguish ourselves as the partner of choice for our clients," said Citadel founder and CEO Kenneth Griffin.