Cost of Capital
By ADAM HAYES Updated October 09, 2021
What Is Cost of Capital?
Understanding Cost of Capital
Real-World Examples
Why Is Cost of Capital Important?
What Is the Difference Between the Cost of Capital and the Discount Rate
What Is Cost of Capital?
Cost of capital is a company's calculation of the minimum return that would be necessary in order to justify undertaking a capital budgeting project, such as building a new factory.
The term cost of capital is used by analysts and investors, but it is always an evaluation of whether a projected decision can be justified by its cost. Investors may also use the term to refer to an evaluation of an investment's potential return in relation to its cost and its risks.
Many companies use a combination of debt and equity to finance business expansion. For such companies, the overall cost of capital is derived from the weighted average cost of all capital sources. This is known as the weighted average cost of capital (WACC).
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Cost Of Capital
Understanding Cost of Capital
The concept of the cost of capital is key information used to determine a project's hurdle rate. A company embarking on a major project must know how much money the project will have to generate in order to offset the cost of undertaking it and then continue to generate profits for the company.
Cost of capital, from the perspective of an investor, is an assessment of the return that can be expected from an acquisition of stock shares or any other investment. This is an estimate and might include best- and worst-case scenarios. An investor might look at the volatility (beta) of a company's financial results to determine whether a stock's cost is justified by its potential return.
Weighted Average Cost of Capital (WACC)
A firm's cost of capital is typically calculated using the weighted average cost of capital formula that considers the cost of both debt and equity capital.
Each category of the firm's capital is weighted proportionately to arrive at a blended rate, and the formula considers every type of debt and equity on the company's balance sheet, including common and preferred stock, bonds, and other forms of debt.
Finding the Cost of Debt
The cost of capital becomes a factor in deciding which financing track to follow: debt, equity, or a combination of the two.
Early-stage companies rarely have sizable assets to pledge as collateral for loans, so equity financing becomes the default mode of funding. Less-established companies with limited operating histories will pay a higher cost for capital than older companies with solid track records since lenders and investors will demand a higher risk premium for the former.
The cost of debt is merely the interest rate paid by the company on its debt. However, since interest expense is tax-deductible, the debt is calculated on an after-tax basis as follows:
Cost of debt=
Total debt
Interest expense
Interest expense=Int. paid on the firm’s current debt
T=The company’s marginal tax rate
The cost of debt can also be estimated by adding a credit spread to the risk-free rate and multiplying the result by (1 - T).
Finding the Cost of Equity
The cost of equity is more complicated since the rate of return demanded by equity investors is not as clearly defined as it is by lenders. The cost of equity is approximated by the capital asset pricing model as follows:
CAPM(Cost of equity)=R
=risk-free rate of return
=market rate of return
Beta is used in the CAPM formula to estimate risk, and the formula would require a public company's own stock beta. For private companies, a beta is estimated based on the average beta among a group of similar public companies. Analysts may refine this beta by calculating it on an after-tax basis. The assumption is that a private firm's beta will become the same as the industry average beta.
The firm’s overall cost of capital is based on the weighted average of these costs.
For example, consider an enterprise with a capital structure consisting of 70% equity and 30% debt; its cost of equity is 10% and the after-tax cost of debt is 7%.
Therefore, its WACC would be:
This is the cost of capital that would be used to discount future cash flows from potential projects and other opportunities to estimate their net present value (NPV) and ability to generate value.
Companies strive to attain the optimal financing mix based on the cost of capital for various funding sources. Debt financing is more tax-efficient than equity financing since interest expenses are tax-deductible and dividends on common shares are paid with after-tax dollars. However, too much debt can result in dangerously high leverage levels, forcing the company to pay higher interest rates to offset the higher default risk
The Difference Between Cost of Capital and the Discount Rate 
The cost of capital and discount rate are somewhat similar and the terms are often used interchangeably. Cost of capital is often calculated by a company's finance department and used by management to set a discount rate (or hurdle rate) that must be beaten to justify an investment.
That said, a company's management should challenge its internally-generated cost of capital numbers, as they may be so conservative as to deter investment.
Cost of capital may also differ based on the type of project or initiative; a highly innovative but risky initiative should carry a higher cost of capital than a project to update essential equipment or software with proven performance.
Real-World Examples
Every industry has its own prevailing average cost of capital.
The numbers vary widely. Homebuilding has a relatively high cost of capital, at 6.35, according to a compilation from New York University's Stern School of Business. The retail grocery business is relatively low, at 1.98%.1
The cost of capital is also high among both biotech and pharmaceutical drug companies, steel manufacturers, Internet software companies, and integrated oil and gas companies. Those industries tend to require significant capital investment in research, development, equipment, and factories.
Among the industries with lower capital costs are money center banks, power companies, real estate investment trusts (REITs), and utilities (both general and water). Such companies may require less equipment or may benefit from very steady cash flows2.
Why Is Cost of Capital Important?
Most businesses strive to grow and expand. There may be many options: expand a factory, buy out a rival, build a new, bigger factory. Before the company decides on any of these options, it determines the cost of capital for each proposed project. This indicates how long it will take for the project to repay what it cost, and how much it will return in the future.

Such projections are always estimates, of course. But the company must follow a reasonable methodology to choose between its options.

What Is the Difference Between the Cost of Capital and the Discount Rate
The two terms are often used interchangeably, but there is a difference.

In business, cost of capital is generally determined by the accounting department. It is a relatively straightforward calculation of the breakeven point for the project.

The management team uses that calculation to determine the discount rate, or hurdle rate, of the project. That is, they decide whether the project can deliver enough of a return to not only repay its costs but reward the company's shareholders3.
Related Terms
What Is the Cost of Equity?
The cost of equity is the rate of return required on an investment in equity or for a particular project or investment. more
How to Calculate the Weighted Average Cost of Capital – WACC
The weighted average cost of capital (WACC) is a calculation of a firm's cost of capital in which each category of capital is proportionately weighted. more
Cost of Debt
Cost of debt is the effective rate that a company pays on its current debt as part of its capital structure.more
Debt Issue
A debt issue is a financial obligation that allows the issuer to raise funds by promising to repay the lender at a certain point in the future. more
Discounted Cash Flow (DCF)
Discounted cash flow (DCF) is a valuation method used to estimate the attractiveness of an investment opportunity. more
Unlevered Cost of Capital
Unlevered cost of capital is an evaluation of a capital project's potential costs made by measuring costs using a hypothetical or debt-free scenario. more
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What Is the Difference Between WACC and IRR?
What Is the Formula for Weighted Average Cost of Capital (WACC)?
CAPM Model: Advantages and Disadvantages
How to Evaluate Firms Using Present Value of Free Cash Flows
Should a Company Issue Debt or Equity?
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