Satya Nadella (pictured), head of Microsoft’s enterprise and cloud division, is expected to be announced as the new CEO of the company, according to reports.

Sources said the company’s board is preparing to announce Nadella as successor to Steve Ballmer, and is also considering replacing co-founder Bill Gates as chairman.

Ballmer announced in August last year that he would be retiring within a year, sparking a wide-ranging search for what would be only the third CEO in Microsoft’s almost 39-year history.

Nadella’s name has been linked with the role for several months, although sources said the plans aren’t yet final. The executive joined Microsoft in 1992 and has led various divisions, including cloud services, server software, internet search and business applications.

Michael Cusumano, a professor at MIT’s Sloan School of Management, told Bloomberg that Nadella would be a good choice as he enjoys a good reputation with Microsoft’s engineering employees.

Ford CEO Alan Mulally was strongly tipped to replace Ballmer due to his turnaround credentials, established when Ford avoided a government bailout in 2009 under his leadership. However, Mulally ruled himself out of the role at the beginning of the month, saying he planned to stay at Ford until at least the end of 2014.

The most recent external candidate linked to the role was Ericsson CEO Hans Vestberg but he has was quick to say he planned to stay at Ericsson.

The next CEO of Qualcomm, Steve Mollenkopf, was also linked to the role before it was announced he would succeed Paul Jacobs at the chipmaker.

Former Nokia CEO Stephen Elop had been seen a contender due to his strong links with Microsoft, having been president of the company’s business division before taking the helm at Nokia in 2010. He subsequently drove the Finnish company’s move towards Microsoft’s Windows Phone as its main smartphone platform.

Other names connected to the role included former Skype boss Tony Bates and current Microsoft COO Kevin Turner.

Microsoft has struggled to keep pace with Apple and Google in the mobile space with its Windows Phone operating system not yet proving the viability of a third mobile ecosystem to rival Android and iOS.

Ballmer’s focus has been more on devices such as the Surface tablet and Xbox gaming console, and offering software over the internet.

But there have been some positive signs for Windows Phone and Microsoft is making a big effort to boost its mobile credentials with the acquisition of Nokia’s Devices & Services unit.

One of the people being considered to replace Gates as chairman is John Thompson, the lead independent director who wrote in a blog post in December that Microsoft will complete its work to find a new CEO in “the early part of 2014″.

Sources said Gates could become more involved with the company, particularly in product development, if he stepped down as chairman, a role he has held since 1981.