Paul Gardner Allen (January 21, 1953 – October 15, 2018) was an American business magnate, investor, and philanthropist. Alongside Bill Gates, Allen co-founded Microsoft in 1975, which helped spark the microcomputer revolution and later became the world's largest PC software company. In March 2018, he was estimated to be the 44th-wealthiest person in the world, with an estimated net worth of $21.7 billion, revised at the time of his death to $20.3 billion.Allen was the founder and Chairman of Vulcan Inc., the privately-held company that managed his various business and philanthropic efforts. He had a multibillion-dollar investment portfolio including technology and media companies, scientific research, real estate holdings, private spaceflight ventures, and stakes in other sectors. He owned two professional sports teams: the Seattle Seahawks of the National Football League and the Portland Trail Blazers of the National Basketball Association, and was part-owner of the Seattle Sounders FC, which joined Major League Soccer in 2009.Allen was the founder of the Allen Institute for Brain Science, Institute for Artificial Intelligence, Institute for Cell Science, Stratolaunch Systems, and Apex Learning. He gave more than $2 billion to causes such as education, wildlife and environmental conservation, the arts, healthcare, community services, and more. He received numerous awards and honors in several different professions, and was listed among the Time 100 Most Influential People in the World in both 2007 and 2008.