Bill Gates is stepping down from the board of Microsoft, the software giant he helped found more than four decades ago.

Gates said on Friday that he would also step down from the board of Berkshire Hathaway, the conglomerate run by his close friend, Warren E. Buffett.

“I have made the decision to step down from both of the public boards on which I serve — Microsoft and Berkshire Hathaway — to dedicate more time to philanthropic priorities including global health and development, education, and my increasing engagement in tackling climate change,” Gates wrote in a LinkedIn post.

For decades, Gates was the face of Microsoft. Known for his technical acumen and ruthless business practices, he helped to establish Microsoft’s Windows software as the primary system for the personal computer. Microsoft said Gates would remain a technical adviser to the company.

Gates has slowly been stepping back from Microsoft in recent years. He left his day-to-day role at the company in 2008 and served as the board’s chairman until 2014.

The company said he wants to devote more of his time to his philanthropy at the Bill & Melinda Gates Foundation, one of the world’s biggest non-profit organisations, which was started with the money he made from Microsoft.

Gates remains one of the largest individual shareholders of Microsoft. As of December, he held more than 100 million shares of Microsoft, roughly 1.3 per cent of the company’s shares. His stock is worth about $16 billion. He said he would remain active at the company and would work closely with Satya Nadella, Microsoft’s chief executive.

“Microsoft will always be an important part of my life’s work and I will continue to be engaged with Satya and the technical leadership to help shape the vision and achieve the company’s ambitious goals. I feel more optimistic than ever about the progress the company is making,” Gates wrote in his post.

Gates has become better known for his work in fighting infectious diseases and climate change. Last month, the Gates Foundation said it would commit an additional $100 million to fight the coronavirus.