If there is a known delay in paying tax (e.g. because of normal tax timing arrangements, or if accumulated losses result in the incremental tax liability arising later) and/or if there is a difference between taxable income and cash flow, then this can
be incorporated by redefining t as the effective tax rate, i.e. the present value at the time the cash inflow occurs, discounting at the after-tax riskless interest rate. For example, if there is a delay in paying tax then some amount I will have to be set aside (and invested) out of the cash inflow Y in order to meet the future tax liability: