The Impact of Personal Income Taxation on Executive Compensation

Abstract

This paper analyzes the effect of personal income taxation on the sensitivity of executive compensation to company performance and the use of stock option and restricted stock grants underlying this sensitivity. The theoretical model predicts that, if a single tax rate applies to the entire compensation package, an increase in the tax rate weakly diminishes the equilibrium level of managerial effort and the after-tax pay-to-performance sensitivity, with the effect on the pre-tax pay-to-performance sensitivity being ambiguous. When salary and option gains are taxed at a higher rate than stock gains, tax changes also induce shifting among the individual compensation instruments. Interestingly, this differential taxation leads to a positive amount of stocks in the compensation contract even in the absence of any desire to incentivize the manager. In addition, an increase in the tax rate applied to salary and option gains may increase the level of managerial effort in equilibrium. On the other hand, an increase in the tax rate applied to stock gains weakly decreases the equilibrium level of managerial effort and strictly decreases the amount of after-tax pay-to-performance sensitivity generated by stock grants. The second part of the paper exploits the variation in the U.S. federal personal income tax rate generated by the Omnibus Budget Reconciliation Act of 1993, as well as variation in the combined federal and state income tax rates during the period 1992-1996 to empirically evaluate the impact of personal income taxation on the pay-to-stock-price sensitivity generated by stock-option and restricted stock grants. The results show that an increase in the ordinary income tax rate decreases the pay-to-stock-price sensitivity generated by option grants when time series variation in the marginal tax rate is utilized in the identification, with the estimates retaining the same sign but being statistically insignificant when only the variation in the marginal tax rate originating from cross-sectional variation in the federal income tax rate and/or state tax rate changes is used in the estimation. On the other hand, stock grant sensitivity is found to be unresponsive to changes in the ordinary income tax rate.