Portfolio Choice with Endogenous Donations - Modeling University Endowments

University endowments differ from other institutions in that donation income and spending rates are of equal importance to asset allocation decisions. Our paper develops an optimal endowment framework with endogenous donations income through a feedback dependence based on investment performance. We investigate both substitution and wealth effects due to incomplete markets and nonlinear donation risk. Looking at empirical data on actual US endowment practices, we validate our donations processes. Large endowments take riskier positions. However, this effect weakens with increasing donation risk, documenting another form of the substitution effect empirically. Spending rates are time varying and determined by relative investment opportunities and the corresponding interaction with endowment size. •We contribute to the under-researched but growing literature on university endowments.•We develop an optimal endowment framework with endogenous donations income through a feedback dependence based on investment performance.•We investigate both substitution and wealth effects due to incomplete markets and nonlinear donation risk.•We look at empirical data on actual US endowment practices and validate our donations processes.•We show that larger endowments take riskier positions but this effect weakens with increasing donation risk.•We show that spending rates are time varying and determined by relative investment opportunities and the corresponding interaction with endowment size.