Microsoft chief Steve Ballmer to retire

Microsoft has announced that chief executive Steve Ballmer will retire within the next 12 months, once it has found a successor.

Mr Ballmer is currently overseeing the transformation of Microsoft into a devices and services company.

He said in a statement: "There is never a perfect time for this type of transition, but now is the right time."

Business Correspondent Mariko Oi said Microsoft had been criticised under Mr Ballmer's leadership.