Ballmer made president
Steve Ballmer's unofficial role as number two at Microsoft was confirmed last week with his promotion to company president.
But the move raised questions about exactly what his boss Bill Gates will be doing in the future.
Ballmer, formerly executive vice president of sales and support, has long been recognised as the most senior Microsoft executive after chairman Gates.
In a memo to staff announcing the promotion, Gates denied that it meant he was pulling back his involvement: 'I'm more enthusiastic about and committed to Microsoft than I've ever been.'
While Gates will focus less on the day-to-day running of Microsoft, the majority of his time would be spent with product groups and on long-term strategy, he added.
At 42, Ballmer is the same age as Gates and a Harvard colleague. He has been responsible for Microsoft's channel efforts and dealing with its large corporate customers.
The bulk of the software giant's senior executives will now report to him, although chief technology officer Nathan Myhrvold will continue to report to Gates.
Both Ballmer and Gates denied the timing of the promotion was linked to Microsoft's current difficulties, notably its antitrust battle with the US Department of Justice.
While questions have been raised over Microsoft's aggressive business actions, Ballmer's reputation as a hard-hitting businessman means it is unlikely to change tack.