Investment with Uncertain Tax Policy: Does Random Tax Policy Discourage Investment
比较了两种不确定性模型（几何布朗运动与随机跳跃）对企业和总投资的影响，发现税收政策不确定性在跳跃模型中可能缩短投资等待时间，而总体资本形成在传统模型中受损、在跳跃模型中可能增强。
We consider the impact of tax policy uncertainty on firm level and aggregate investment, comparing investment behavior when uncertainty is due to a shock following Geometric Brownian Motion (GBM) versus when random discrete jumps in tax policy occur. Expectations of the likelihood of a tax policy switch have an important negative impact on the gain to delaying investment in the latter model and time to investment can fall with increasing tax policy uncertainty. Aggregate investment simulations indicate that capital formation is adversely affected by increases in uncertainty in the traditional GBM model but can be enhanced in the jump process model. We also find that mean preserving spreads are attractive to firms when they have discretion over real behavior. In both models, a mean preserving spread lowers the cost of capital conditional on investment as firms shift investment from high to low cost periods. Ex ante mean preserving spreads in general lead to ex post decreases in the price of capital. We relate this 1 It is often said that nothing is certain in life except death and taxes. While death is