Microsoft co-founder Bill Gates is stepping down from the company's board to spend more time on philanthropic activities, BBC News reported.

He says he wants to focus on global health and development, education, and tackling climate change.

One of the world's richest men, Gates, 65, has also left the board of Warren Buffett's massive holding company, Berkshire Hathaway.

Gates stepped down from his day-to-day role running Microsoft in 2008.

He is listed by Forbes as the world's second richest man, and is worth $103.6bn.

Bill Gates made his fortune developing software for the personal computer.