Lilly Endowment Inc., headquartered in Indianapolis, Indiana, is one of the world's largest private philanthropic foundations and among the largest endowments in the United States. It was founded in 1937 by Josiah K. Lilly Sr. and his sons, Eli Jr. and Josiah Jr. (Joe), with an initial gift of Eli Lilly and Company stock valued at $280,000 USD. As of 2025, its total assets were $106 billion.