Microsoft COO Kevin Turner is leaving the company at the end of this month to become CEO of Citadel Securities.

Turner will also be vice chairman of Citadel, the parent company. He has been COO of Microsoft since 2005.

He was in the race for the CEO role that went to Satya Nadella when former CEO Steve Ballmer stepped down in 2014.

Several reports suggest that he has been searching for a CEO job for several years.

Before joining Microsoft, Turner held several management positions at Wal-Mart, including president and CEO of Sam’s Club, for about 20 years.

Turner led Microsoft’s global sales, field, marketing and services organisations, as well as the partner channel.

In an email to employees, Nadella said: "He built the sales force into the strategic asset it is today with incredible talent while at the same time more than doubling our revenue and driving customer satisfaction scores to the highest in company history."

Nadella said that he and Turner had been discussing on what should be done in sales and support to help Microsoft continue to reach for the next level of customer centricity and obsession.

Turner’s responsibilities will now be divided among five different executives at Microsoft.

Microsoft International head Jean-Philippe Courtois will take over global sales, marketing and operations, while Judson Althoff will lead the worldwide commercial business.

Chris Capossela will lead the worldwide marketing and consumer business arty stores, while corporate strategy head Kurt DelBene will add IT and operations to his portfolio.

The company’s CFO Amy Hood will also lead the existing SMSG finance team and WWLP, in addition to the central finance team.

Cortois and Althoff will also join Nadella’s senior leadership team.