After 13 entertaining, notoriously abrasive years running Microsoft from his Redmond cockpit, Steve Ballmer is to step down as CEO within a year, it has been announced. The firm’s stock price rose sharply at the news.

Despite the pressure Ballmer must have been under since a series of strategic mis-steps culminating with the shocking near debacle of Windows 8, the news that Microsoft has decided to institute a generational shift is still a surprise.

“There is never a perfect time for this type of transition, but now is the right time,” Ballmer admitted in a prepared statement.

“We have embarked on a new strategy with a new organization and we have an amazing Senior Leadership Team. My original thoughts on timing would have had my retirement happen in the middle of our company’s transformation to a devices and services company. We need a CEO who will be here longer term for this new direction.”

A “special committee” chaired by independent director John Thompson and Microsoft Chairman Bill Gates had been appointed to look for a successor, Microsoft said.

“As a member of the succession planning committee, I’ll work closely with the other members of the board to identify a great new CEO. We’re fortunate to have Steve in his role until the new CEO assumes these duties,” said Gates.

The use of a relative outsider to head the committee and the inclusion of a quote from Gates in the release is bound to be seen as significant, something that shapes the whole atmosphere of the Ballmer’s stepping down.

It was Gates who, bearing in mind his own mistakes at the helm of Microsoft, tried to complement the senior team with interesting thinkers such as Ray Ozzie, who took over Gate’s role as ‘chief software architect’ in 2006. A big advocate of the cloud and a predictor of doom for Windows, Ozzie was sidelined by Ballmer and lasted less than four years. By the end he cut a quietly bemused figure.

Except that Ozzie was right; Windows was profitable but obsolete and a new plan would soon be needed that turned away from the 1990's desktop concept.

Ballmer is going but the implication is that the decision was not only his to make. Likely the deeper reasons behind the news will take a forensic biographer to untangle when such a book is written.

In an internal Microsoft email circulated to the press, Ballmer said:

"This is an emotional and difficult thing for me to do. I take this step in the best interests of the company I love; it is the thing outside of my family and closest friends that matters to me most." Heartrending.

The possibility of a candidate not currently working at Microsoft taking the helm now looks at least possible. Not long ago such a move would have been seen as unthinkable.

Ballmer joined Microsoft in 1980, employee number 30, so he is in this firm for life. His next job role, if any, has not been announced.