Microsoft chief Steve Ballmer to retire within a year

Steve Ballmer, who is 57, will retire as chief executive of Microsoft within the next 12 months, once a successor has been chosen.

Ballmer has worked for Microsoft for 33 years and is currently overseeing the transformation of Microsoft into a devices and services company.

"There is never a perfect time for this type of transition, but now is the right time," Ballmer said in a statement. "We need a CEO who will be here longer term for this new direction."

Microsoft's board has appointed a special committee to direct the process of appointing a new CEO. It will consider both external and internal candidates and is working with executive recruiting firm Heidrick & Struggles International, according to the company.

Microsoft's share price rose around 9pc in pre-market trading and was up 7.5 per cent at $35 (£22) in early trades. Ballmer owns 4pc of the company, making his stake worth some $12bn.

Ballmer joined Microsoft in June 1980 and became Microsoft's 30th employee - the first business manager hired by former chief executive and current chairman Bill Gates.

During the subsequent 20 years, Ballmer headed several Microsoft divisions, including operations, operating systems development, and sales and support. He was officially named Chief Executive Officer in January 2000, though it wasn't until Bill Gates resigned in 2009 that Ballmer was able to shift the company's focus away from PCs.

Under Ballmer's tenure as CEO, Microsoft’s annual revenue has surged from $25 billion to over $70 billion, while its net income has increased 215 percent to $23 billion.

Although these gains have come from the existing Windows and Office franchises, Ballmer also built new businesses such as the data centres division and the Xbox entertainment and devices division.

Ballmer is known for his exuberant persona, which is intended to motivate employees and partners. His flamboyant stage appearances at Microsoft events have been widely circulated on the Internet as viral videos.