Note: non-Hong Kong tax laws are important for Hong Kong accountants, because these laws are often the reason why your clients/employers are doing business in Hong Kong.
Instrument | Annualized Return |
|
---|---|---|
I. | Money Market Fund | $r(1-t)$ |
II. | SPDA | $[(1+r)^{n}(1-t)+t]^{1/n} -1$ |
III. | Mutual Fund | $r(1 - g)$ |
IV. | Foreign Corporation | $[(1+r)^{n}(1-g)+g]^{1/n} -1$ |
V. | Insurance Policy | $r$ |
VI. | Pension | $r$ |
Suppose there is a riskless financial asset that costs one dollar at the beginning of the period and pays $1 + r$ dollars at the end of every period. The difference, $r$, is taxed at rate $t$.
Thus, it is possible to borrow and lend at the after-tax rate of $r(1 - t)$ per period. There is also a real asset costing $x > 0$. The asset produces a riskless pretax cash flow of $k$ in perpetuity at the end of each period.
For tax purposes, the original cost of the asset may be depreciated straight line at rate $0 \leq d \leq 1$. Taxable income for any period is the pretax cash flow less the depreciation.
But wait!?!? Didn't you just tell us not to consider depreciation?
Tax is paid at rate $t$, so that at the end of the first period, the net-of-tax cash flow is
$$k-t(k-dx)$$Depreciation is impacting cash flow through it's impact on the taxes you pay!
We can rewrite the net-of-tax cash flow equation above as follows:
$$k(1-t) + dtx$$Now lets write down the cash flows from this project, and discount them.
The cash outflow $x$ to acquire the asset is not tax deductible, so the first cash flow is just:
$$-x$$The second set of cash flows are the net-of-tax cash flows over the depreciable life of the asset discounted back to time zero at the after-tax rate of return
$$ \sum^{1/d}_{n=1}\frac{k(1-t)+dtx}{[1+r(1-t)]^{n}}$$The final set of cash flows we need to consider are then net-of-tax cash flows from the asset after the asset is fully depreciated.
$$\sum^{\infty}_{n=1+1/d}\frac{k(1-t)}{[1+r(1-t)]^{n}}$$So the total net-of-tax present value of these cash flows at the end of the first period is: $$-x + \sum^{1/d}_{n=1}\frac{k(1-t)+dtx}{[1+r(1-t)]^{n}}+\sum^{\infty}_{n=1+1/d}\frac{k(1-t)}{[1+r(1-t)]^{n}}$$
This is using the annuity and perpetuity formulas.
The first term is the cost of the asset again.
The second term is the present value of the perpetual pre-tax cash flow from the asset, $k$, capitalized at the pre-tax rate, $r$. Note that this is the same as the after tax cash flow, $k(1-t)$, capitalized at the after tax discount rate, $r(1-t)$.
First let's plot the value of the tax shield as a function of the depreciation rate. Assume that $r=10\%$, and $t=30\%$
import matplotlib.pyplot as plt
import numpy as np
def tax_shield(d,t,r,x=1):
first_term = (d*x*t)/(r*(1-t))
second_term = 1-(1+r*(1-t))**(-1/d)
return first_term*second_term
First let's plot the value of the tax shield as a function of the depreciation rate. Assume that $r=10\%$, and $t=30\%$
D = np.linspace(0.01,1,100)
plt.plot(D,tax_shield(D,t=0.3,r=0.1))
plt.xlabel('Depreciation rate')
plt.ylabel('Tax shield')
plt.show()
First let's plot the value of the tax shield as a function of the depreciation rate. Now let's plot the value of the tax shield as a function of the tax rate. Assume that $r=10\%$, and $d=30\%$
T = np.linspace(0.01,1,100)
plt.plot(T,tax_shield(d=0.3,t=T,r=0.1))
plt.xlabel('Tax rate')
plt.ylabel('Tax shield')
plt.show()
tax_shield(d=0.3,t=.999999999,r=0.1)
1.0000001100223055