We study the effect of introducing a nonredundant derivative on the volatilities of the stock market return and the locally risk-free interest rate. Our analysis uses a standard, frictionless, full-information, dynamic, continuous-time, general-equilibrium, Lucas endowment economy in which there...

Households with familiarity biases tilt their portfolios toward a few risky assets. The resulting mean-variance loss from portfolio underdiversification is equivalent to only a modest reduction of about 1 percent per year in a household's portfolio return. However, once we consider also the...