Weighted Average Cost of Capital (WACC)

What Is the Weighted Average Cost of Capital (WACC)?

The weighted average cost of capital (WACC) represents a firm's average cost of capital from all sources, including common stock, preferred stock, bonds, and other forms of debt.

The weighted average cost of capital is a common way to determine required rate of return because it expresses, in a single number, the return that both bondholders and shareholders demand in order to provide the company with capital. A firm’s WACC is likely to be higher if its stock is relatively volatile or if its debt is seen as risky because investors will demand greater returns. 

Key Takeaways

  • WACC represents a firm's cost of capital in which each category of capital is proportionately weighted.
  • WACC is commonly used as a hurdle rate against which companies and investors can gauge the desirability of a given project or acquisition.
  • WACC is also used as the discount rate for future cash flows in discounted cash flow analysis.
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Weighted Average Cost Of Capital (WACC)

Understanding WACC

In corporate finance, determining a company’s cost of capital is vital for a couple of important reasons. For instance, WACC is the discount rate that a company uses to estimate its net present value.

WACC is also important when analyzing the potential benefits of taking on projects or acquiring another business. If the company believes that a merger, for instance, will generate a return higher than its cost of capital, it’s likely a good choice for the company. If its management anticipates a return lower than what their own investors are expecting, they’ll want to put their capital to better use.

In most cases, a lower WACC indicates a healthy business that’s able to attract investors at a lower cost. By contrast, a higher WACC usually coincides with businesses that are seen as riskier and need to compensate investors with higher returns. 

If a company only obtains financing through one source—say, common stock—calculating its cost of capital would be relatively simple. If investors expected a rate of return of 10% in order to purchase shares, the firm’s cost of capital would be the same as its cost of equity: 10%. 

The same would be true if the company only used debt financing. For example, if the company paid an average yield of 5% on its outstanding bonds, its cost of debt would be 5%. This is also its cost of capital.

However, many companies generate capital from a combination of debt and equity (such as stock) financing. In order to express the cost of capital in a single figure, one has to weigh its cost of debt and cost of equity proportionally based on how much financing is acquired through each source. 

WACC Formula and Calculation

WACC = ( E V × R e ) + ( D V × R d × ( 1 T c ) ) where: E = Market value of the firm’s equity D = Market value of the firm’s debt V = E + D R e = Cost of equity R d = Cost of debt T c = Corporate tax rate \begin{aligned} &\text{WACC} = \left ( \frac{ E }{ V} \times Re \right ) + \left ( \frac{ D }{ V} \times Rd \times ( 1 - Tc ) \right ) \\ &\textbf{where:} \\ &E = \text{Market value of the firm's equity} \\ &D = \text{Market value of the firm's debt} \\ &V = E + D \\ &Re = \text{Cost of equity} \\ &Rd = \text{Cost of debt} \\ &Tc = \text{Corporate tax rate} \\ \end{aligned} WACC=(VE×Re)+(VD×Rd×(1Tc))where:E=Market value of the firm’s equityD=Market value of the firm’s debtV=E+DRe=Cost of equityRd=Cost of debtTc=Corporate tax rate

WACC is calculated by multiplying the cost of each capital source (debt and equity) by its relevant weight and then adding the products together. In the above formula, E/V represents the proportion of equity-based financing, while D/V represents the proportion of debt-based financing. The WACC formula thus involves the summation of two terms:

( E V × R e ) \left ( \frac{ E }{ V} \times Re \right ) (VE×Re)

( D V × R d × ( 1 T c ) ) \left ( \frac{ D }{ V} \times Rd \times ( 1 - Tc ) \right ) (VD×Rd×(1Tc))

The former represents the weighted value of equity capital, while the latter represents the weighted value of debt capital.

Suppose that a company obtained $1,000,000 in debt financing and $4,000,000 in equity financing by selling common shares. E/V would equal 0.8 ($4,000,000 ÷ $5,000,000 of total capital) and D/V would equal 0.2 ($1,000,000 ÷ $5,000,000 of total capital). 

Calculating WACC in Excel

The weighted average cost of capital (WACC) can be calculated in Excel. The biggest challenge is sourcing the correct data to plug into the model. See Investopedia’s notes on how to calculate WACC in Excel.

Explaining the Formula Elements

Cost of equity (Re) can be a bit tricky to calculate because share capital does not technically have an explicit value. When companies reimburse bondholders, the amount they pay has a predetermined interest rate. On the other hand, equity has no concrete price that the company must pay. As a result, companies have to estimate cost of equity—in other words, the rate of return that investors demand based on the expected volatility of the stock. 

Because shareholders will expect to receive a certain return on their investments in a company, the equity holders' required rate of return is a cost from the company's perspective; if the company fails to deliver this expected return, shareholders will simply sell off their shares, which leads to a decrease in share price and in the company’s value. The cost of equity, then, is essentially the total return that a company must generate in order to maintain a share price that will satisfy its investors.

Companies typically use the Capital Asset Pricing Model (CAPM) to arrive at the cost of equity (in CAPM, it’s called the expected return of investment). Again, this is not an exact calculation because firms have to lean on historical data, which can never accurately predict future growth.

Determining the cost of debt (Rd), on the other hand, is a more straightforward process. This is often done by averaging the yield to maturity for a company’s outstanding debt. This method is easier if you’re looking at a publicly traded company that has to report its debt obligations.

For privately owned companies, one can look at the company’s credit rating from firms like Moody’s and S&P and then add a relevant spread over risk-free assets (for example, Treasury notes of the same maturity) to approximate the return investors would demand.

Businesses are able to deduct interest expenses from their taxes. Because of this, the net cost of a company's debt is the amount of interest it is paying minus the amount it has saved in taxes. This is why Rd (1 - the corporate tax rate) is used to calculate the after-tax cost of debt. 

Who Uses WACC?

Securities analysts may use WACC when assessing the value of investment opportunities. For example, in discounted cash flow analysis, one may apply WACC as the discount rate for future cash flows in order to derive a business's net present value. 

WACC may also be used internally by the finance team as a hurdle rate for pursuing a given project or acquisition. If the company’s investment in a new manufacturing facility, for example, has a lower rate of return than its WACC, the company will probably hold back and find other uses for that money.  

WACC vs. Required Rate of Return (RRR)

The required rate of return (RRR) is the minimum rate an investor will accept for a project or investment. If they expect a smaller return than what they require, they’ll allocate their money elsewhere. 

One way to determine the RRR is by using the CAPM, which uses a stock’s volatility relative to the broader market (its beta) to estimate the return that stockholders will require.

Another method for identifying the RRR is by calculating the WACC. The advantage of using WACC is that it takes the company’s capital structure into account—that is, how much it leans on debt financing versus equity.

Limitations of WACC

The WACC formula seems easier to calculate than it really is. Because certain elements of the formula, such as the cost of equity, are not consistent values, various parties may report them differently for different reasons. As such, although WACC can often help lend valuable insight into a company, one should always use it along with other metrics when determining whether or not to invest in a company.

Example of How to Use WACC

As an example, consider a hypothetical manufacturer called XYZ Brands. Suppose the book value of the company’s debt is $1,000,000 and its market capitalization (or the market value of its equity) is $4,000,000. 

Let’s further assume that XYZ’s cost of equity—the minimum return that shareholders demand—is 10%. Here, E/V would equal 0.8 ($4,000,000 of equity value divided by $5,000,000 of total financing). Therefore, the weighted cost of equity would be .08 (0.8 x .10). This is the first half of the WACC equation.

Now we have to figure out XYZ’s weighted cost of debt. To do this, we need to determine D/V; in this case, that’s 0.2 ($1,000,000 in debt, divided by $5,000,000 in total capital). Next, we would multiply that figure by the company’s cost of debt, which we’ll say is 5%. Lastly, we multiply the product of those two numbers by 1 minus the tax rate. So if the tax rate is .025, “1 minus Tc” is equal to 0.75. 

In the end, we arrive at a weighted cost of debt of .0075 (0.2 x .05 x 0.75). When that’s added to the weighted cost of equity (.08), we get a WACC of .0875, or 8.75% (0.08 weighted cost of equity + 0.0075 weighted cost of debt). 

That represents XYZ’s average cost to attract investors and the return that they’re going to expect, given the company’s financial strength and risk compared to other opportunities. 

What Is Weighted Average Cost of Capital (WACC)?

The weighted average cost of capital represents the average cost to attract investors, whether they're bondholders or stockholders. The calculation weights the cost of capital based on how much debt and equity the company uses, which provides a clear hurdle rate for internal projects or potential acquisitions. 


Who Uses Weighted Average Cost of Capital?

WACC is used in financial modeling (it serves as the discount rate for calculating the net present value of a business). It’s also the “hurdle rate” that companies use when analyzing new projects or acquisition targets. If the company’s allocation can be expected to produce a return higher than its own cost of capital, then it’s typically a good use of funds. 


Are WACC and Required Rate of Return (RRR) the Same?

The weighted average cost of capital is one way to arrive at the required rate of return—that is, the minimum return that investors demand from a particular company. A key advantage of WACC is that it takes the company’s capital structure into consideration. If a company primarily uses debt financing, for instance, its WACC will be closer to its cost of debt than its cost of equity.


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  2. SoFi. "Introduction to Weighted Average Cost of Capital." Accessed Nov. 2, 2021.

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  4. Corporate Finance Institute. "Cost of Debt." Accessed Nov. 2, 2021.

  5. Corporate Finance Institute. "Required Rate of Return." Accessed Nov. 2, 2021.