Paul Allen was best known for his stake in Microsoft, but his $20 billion fortune was mostly tied to the real estate, private equity, and energy sectors. Allen owned more than one million square feet of retail, office, and industrial space in California, New York, Washington, and Oregon. He was involved in Uber, DreamWorks, Plains All America, and Ticketmaster. At the time of his death in 2018, Paul Allen was the chairman of Charter Communications, and founder and chairman of Vulcan Inc., his private asset management company. Allen had a multi-billion dollar investment portfolio that included investments in over 40 other media, technology, and content companies. He was also a member of the billionaire space club. Allen's Vulcan Aerospace financed the Spaceship One effort and won the $10 million Ansari X Prize in 2004. Allen sold the technology behind SpaceShipOne to Richard Branson. (Which then developed into SpaceShipTwo.