Microsoft CEO Ballmer to retire
Microsoft CEO Steve Ballmer, who succeeded founder Bill Gates in the job, will retire within the next 12 months.
The world's biggest software company did not name a successor.
Microsoft Corp's stock shot up 9% in pre-market trading following the news.
Mr Ballmer, 57, first met Microsoft founder Bill Gates in 1973 while they were living down a dormitory hall from each other at Harvard University.
He joined Microsoft in 1980 to bring some business discipline and salesmanship to a company that had just landed a contract to supply an operating system for a personal computer that IBM would release in 1981.
Mr Ballmer did the job so well that he would become Mr Gates' sounding board and succeed him as CEO in 2000.