Paul Gardner Allen (January 21, 1953 – October 15, 2018) was an American business magnate, researcher, investor, and philanthropist. He is best known for co-founding Microsoft Corporation alongside Bill Gates in 1975, which helped spark the microcomputer revolution of the 1970s and 1980s and later became the world's largest personal computer software company. Allen was ranked as the 44th-wealthiest person in the world by Forbes in 2018, and had an estimated net worth of $20.3 billion at the time of his death.