Duke originally placed in the trust securities worth $40 million, mostly stock in the Duke Power Company. He died in October 1925, and by his will added approximately $67 million more to the trust, thus making it one of the largest philanthropies in the nation at that time. Under the terms of the indenture creating the trust, Duke specified that nearly one-third of the annual income from the trust was to go to a new research university, Duke University, that was to be organized around Trinity College, an existing liberal arts college in Durham. Thirty-two percent was to go for the building and support of nonprofit community hospitals for white and African American people in North Carolina and South Carolina. The remainder of the income was to be divided, according to ratios spelled out in the indenture, among Davidson College, Furman University, Johnson C. Smith University, child-care institutions for children of both races in the Carolinas, and certain Methodist purposes in North Carolina (the building and support of rural Methodist churches and assistance to retired Methodist preachers and their dependents).
Headquartered in Charlotte, the Duke Endowment is overseen by a self-perpetuating board of 12 trustees. In the early 2000s it had assets of approximately $2.5 billion, making it by the far the largest private foundation in North Carolina and among the largest in the United States. Duke Endowment grants since 1924 have surpassed $1.6 billion.