William Henry Gates III (born October 28, 1955) is an American business magnate, investor, author, philanthropist, and co-founder of the Microsoft Corporation along with Paul Allen. Gates and Allen launched Microsoft in 1975, 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. In January 2000, Gates stepped down as chief executive officer of Microsoft. 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 stepped down as chairman of Microsoft in February 2014 and assumed a new post as technology adviser to support the newly appointed CEO Satya Nadella. Gates is one of the best-known entrepreneurs of the personal computer revolution. Later in his career, Gates pursued a number of philanthropic endeavors. He donated large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation, which was established in 2000. Gates has been included in the Forbes list of the world's wealthiest people, an index of the wealthiest documented individuals, excluding and ranking against those with wealth that is not able to be completely ascertained. From 1995 to 2009, he held the Forbes title of the richest person in the world all but four of those years, and held it consistently from 2014–July 2017, with an estimated net worth of US$89.9 billion as of October 2017. In December 2017, Gates has become number one richest person in the world till now.