Discount

See also: Discounts and allowances

In finance and economics, discounting is the process of finding the present value of an amount of cash at some future date, and along with compounding cash forms the basis of time value of money calculations. The discounted value of a cash flow is determined by reducing its value by the appropriate discount rate for each unit of time between the time when the cashflow is to be valued to the time of the cash flow. Most often the discount rate is expressed as an annual rate.

Contents

Example

To calculate the present value of a single cash flow, it is divided by one plus the interest rate for each period of time that will pass. This is expressed mathematically as raising the divisor to the power of the number of units of time.

Consider the task to find the present value PV of $100 that will be received in five years. Or equivalently, which amount of money today will grow to $100 in five years when subject to a constant discount rate?

Assuming a 12% per year interest rate it follows

{\rm PV}=\frac{$100}{(1+0.12)^5}=$56.74.

Discount rate

The discount rate which is used in financial calculations is usually chosen to be equal to the cost of capital. Some adjustment may be made to the discount rate to take account of risks associated with uncertain cashflows, with other developments.

The discount rates typically applied to different types of companies show significant differences:

Reason for high discount rates for startups:

One method that looks into a correct discount rate is the capital asset pricing model. This model takes in account three variables that make up the discount rate:

1. Risk Free Rate: The percentage of return generated by investing in risk free securities such as government bonds.

2. Beta: The measurement of how a company’s stock price reacts to a change in the market. A beta higher than 1 means that a change in share price is exaggerated compared to the rest of shares in the same market. A beta less than 1 means that the share is stable and not very responsive to changes in the market. Less than 0 means that a share is moving in the opposite of the market change.

3. Equity Market Risk Premium: The return on investment that investors require above the risk free rate.

Discount rate= risk free rate + beta*(equity market risk premium)

Discount factor

The discount factor, P(T), is the number which a future cash flow, to be received at time T, must be multiplied by in order to obtain the current present value. Thus, a fixed annually compounded discount rate is

P(T) = \frac{1}{(1+r)^T}

For fixed continuously compounded discount rate we have

P(T) = e^{-rT} \,

Other discounts

For discounts in marketing, see discounts and allowances, sales promotion, and pricing.

External links

See also

Lists