Kent A. Smetters and Walter Theseira
Abstract —Security markets between generations are naturally incomplete in a laissez-faire economy since risk sharing agreements cannot be made with the unborn. But suppose that generations could trade if, for example, a representative of the unborn negotiated on their behalf today. What would the trades look like? Can government fiscal policy be used to replicate these trades? Would completing this missing market be Pareto improving when the introduction of the new security changes the prices of existing assets? This paper characterizes analytically the hypothetical trades between generations and shows how the government can replicate these trades by taxing the realized equity premium on investments in a symmetric fashion. This tax is equivalent to the government providing a “collar-like” guarantee on personal investments. When technology shocks are mostly driven by changes in depreciation, a positive tax (a long collar) replicates the hypothetical trades; this tax is also Pareto improving under fairly general conditions. When technology shocks are mostly driven by changes in productivity, the choice between a positive and negative tax rate is unclear. However, with log utility, Cobb-Douglas production, and a depreciation rate less than 100 percent, a negative tax (short collar) is Pareto improving. Simulation analysis is used to consider more complicated cases, including when depreciation and productivity are both uncertain. Under the baseline calibration for the U.S., a positive tax (a long collar) on the equity premium is Pareto improving.
[Keywords: Social Security, Trust, Pension, System, Countries, Workers, Private, Reform, Demographic, Model]