Allen left active operations at Microsoft in early 1983 after a Hodgkin lymphoma diagnosis, remaining on its board as vice chairman. He and his sister, Jody Allen, founded Vulcan Inc. in 1986, a privately held company that managed his various business and philanthropic efforts. He had a multi-billion dollar investment portfolio including technology and media companies, scientific research, real estate holdings, private space flight ventures, and stakes in other sectors. He owned 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 of Major League Soccer. In 2000 he resigned from his position on Microsoft's board and assumed the post of senior strategy advisor to the company's management team.