William Henry "Bill" Gates III (1955) 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, and was the largest individual shareholder until May 2014. Gates has authored and co-authored several books. Since 1987, Gates has been included in the Forbes list of the world's wealthiest people and was the wealthiest from 1995 to 2007, again in 2009, and has been since 2014. Between 2009 and 2014, his wealth doubled from US$40 billion to more than US$82 billion. Between 2013 and 2014, his wealth increased by US$15 billion. Gates is currently the richest person in the world, with an estimated net worth of US$85.6 billion as of February 2017.