Optimal timing and capacity choice with taxes and subsidies under uncertainty

We develop a real options model that examines the effect of government's subsidies and taxation policy on the timing and size of investments. We find that a higher depreciation rate or subsidy, or a lower tax rate, accelerates investments. The effect of subsidies on the investment size depends on whether the subsidy is fixed or variable: a fixed subsidy induces smaller size investments, whereas a variable subsidy encourages larger size investments. The tax and depreciation rates do not affect the size of the investment. For revenue-neutral incentive packages, the effect of changes in the above variables on the investment timing and size is not necessarily monotonic and it depends on the instrument of the tax-subsidy policy that is used to keep the new policy revenue neutral. There are also economic contexts in which an increase in the tax rate can accelerate investments of a larger scale.