Claim: The largest individual shareholder of Microsoft was Bill Gates.

William Henry Gates III -LRB- born October 28 , 1955 -RRB- is the co-founder of Microsoft and is an American business magnate , investor , author and philanthropist .   In 1975 , Gates and Paul Allen co-founded Microsoft , which became the world 's largest PC software company . During his career at Microsoft , Gates held the positions of chairman , CEO and chief software architect , while also being the largest individual shareholder until May 2014 . Gates stepped down as chief executive officer of Microsoft in January 2000 , but he remained as chairman and created the position of chief software architect for himself . In June 2006 , Gates announced that he would be transitioning from full-time work at Microsoft to part-time work and full-time work at the Bill & Melinda Gates Foundation . He gradually transferred his duties to Ray Ozzie and Craig Mundie . He stepped down as chairman of Microsoft in February 2014 , taking on a new post as technology adviser to support the then newly appointed CEO Satya Nadella .   Gates is one of the best-known entrepreneurs of the personal computer revolution . He has been criticized for his business tactics , which have been considered anti-competitive , an opinion that has in some cases been upheld by numerous court rulings . Later in his career , Gates pursued a number of philanthropic endeavors , donating large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation , established in 2000 .   Since 1987 , Gates has been included in the Forbes list of the world 's wealthiest people . Gates is the richest person in the world , with an estimated net worth of US$ 88.5 billion . In 2009 , Gates and Warren Buffett founded The Giving Pledge , whereby they and other billionaires pledge to give at least half of their wealth to philanthropy .