The cost of capital is the minimum required return on an investment to compensate investors for the use of their funds. It is the same as the appropriate discount rate for a project's cash flows. It is crucial to remember that the cost of capital depends primarily on the risk of the investment, not on the source of the funds used to finance it.
Key takeaway: The cost of capital depends primarily on the use of the funds, not the source.
The cost of equity is the return a firm's equity investors require on their investment. It is the most difficult component of capital costs to estimate because it cannot be directly observed from the market. We explore two primary methods for estimating it.
The DGM estimates the cost of equity based on the assumption that a firm's dividends will grow at a constant rate forever. The cost of equity ($R_E$) is the sum of the dividend yield and the constant growth rate.
Where \(D_1\) is the expected dividend in one period, \(P_0\) is the current stock price, and \(g\) is the constant growth rate.
The SML approach, based on the Capital Asset Pricing Model (CAPM), explicitly accounts for risk. It states that the expected return on a risky asset is a function of the risk-free rate, the market risk premium, and the asset's systematic risk (beta).
Where \(R_f\) is the risk-free rate, \((R_M - R_f)\) is the market risk premium, and \(\beta_E\) is the stock's beta.
The cost of debt ($R_D$) is the return that the firm's creditors require on new borrowing. The correct measure is the yield to maturity (YTM) on the firm's existing debt, not the coupon rate. We must use the after-tax cost of debt for the WACC calculation because interest payments are tax-deductible.
The cost of preferred stock ($R_P$) pays a fixed dividend forever, making it a perpetuity. The cost of preferred stock is therefore the dividend divided by the current price of the stock. It is not tax-deductible for the firm, so there is no after-tax adjustment.
Where \(D\) is the fixed dividend and \(P_0\) is the current price per share.
The WACC is the firm's overall cost of capital. It's a blended rate that reflects the costs of all sources of financing (equity, debt, preferred stock) weighted by their proportion in the firm's capital structure. The weights are determined by the market value of each financing source.
Where \(T_C\) is the corporate tax rate.
A firm's WACC is the appropriate discount rate for projects that have the same risk as the firm's existing operations. This is often called the "hurdle rate." Using the WACC as a universal discount rate for all projects can lead to incorrect decisions.
When a company raises new capital, it incurs flotation costs (e.g., underwriting spreads, legal fees). These costs are relevant to the capital budgeting decision and should be treated as part of the initial project cost, not by adjusting the WACC. We calculate a weighted average flotation cost ($f_A$) based on the target capital structure. The true initial cost of a project is the funding need divided by $(1 - f_A)$.
Where \(f_E\), \(f_D\), and \(f_P\) are the flotation costs for equity, debt, and preferred stock, respectively.
For WACC calculations, the weights used for each component of capital must be based on their current market values, not their book values from the balance sheet. This is because the market values reflect the true, current economic value of the firm's financing, while book values are historical accounting figures that may not be relevant to today's investment decisions.
A firm's WACC represents the appropriate discount rate for projects that have the same risk as the firm's existing operations. This is often called the "hurdle rate." A key pitfall is using the WACC as a universal discount rate for all projects. This can lead to:
To mitigate this, the pure play approach can be used for projects with significantly different risk profiles. This involves finding a publicly traded company that operates exclusively in a similar business and using its cost of capital as a proxy for the project's discount rate.