David Booth (born December 2, 1946) is an American businessman and philanthropist best known as the co-founder of Dimensional Fund Advisors with Rex Sinquefield. After studying under Nobel laureate Eugene Fama at the University of Chicago, he helped create some of the world's first index funds at Wells Fargo in the 1970s before launching Dimensional in 1981, which grew to manage around $800 billion in assets. His investment approach, rooted in the efficient market hypothesis, pioneered what is now called factor investing. Booth has donated over $300 million to the University of Chicago (renaming its business school) and more than $50 million to the University of Kansas for athletic facilities, including a football stadium renovation. In 2010, he famously purchased Dr. James Naismith's original 1891 rules of basketball for $3.8 million and donated them to the University of Kansas. With a net worth of $2 billion, he remains chairman of Dimensional, having stepped back as CEO in 2017.