Microsoft’s long-serving and sometimes controversial CEO, Steve Ballmer, 57, will step down from the US software company within the next 12 months. This will happen after the conclusion of a process to choose his successor, the company says in a statement.

The news sent Microsoft’s share price rocketing higher by more than 8% in premarket trading on the Nasdaq in New York, shortly after the announcement was made.

Ballmer, who took the reins from his friend Bill Gates in January 2000, will continue as CEO for now and will “lead Microsoft through the next steps of its transformation to a devices and services company”, the company says in the statement.

Ballmer’s tenure has been controversial, with the company’s share price treading water for most of the time he has been at the helm. Like many other consumer technology companies, Microsoft was slow to respond to the shift from the PC-centric model of computing to mobile and cloud services.

When Ballmer took over from Gates, Microsoft ruled over the technology landscape with an iron first. Today, Apple and Google — a company that was less than 18 months old when he took the top job — are both valued higher by market capitalisation.

“There is never a perfect time for this type of transition, but now is the right time,” Ballmer says in the statement. “We have embarked on a new strategy with a new organisation 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.”

Born in Detroit to a Swiss-immigrant father and Jewish mother, Ballmer grew up in Farmington Hills, Michigan. He achieved a perfect score on the mathematics portion of the SAT — the standardised test for most college admissions in the US — and studied applied mathematics and economics at Harvard University, where he finished magna cum laude.

Ballmer joined Microsoft as a business manager in June 1980. He was the company’s 30th employee and when the company was incorporated in 1981 and he held 8% of the company’s stock. In 2003, he reduced this stake to 4%.

During his more than 30 years with Microsoft, Ballmer headed a number of divisions and served as company president.

The company says its board has appointed a special committee to direct the process of appointing a new CEO.

The committee will be chaired by John Thompson, the board’s lead independent director, and includes Gates. Chairman of the audit committee Chuck Noski and chairman of the compensation committee Steve Luczo make up its other members.