WACC vs CAPM: How They Differ and Work Together
What Is WACC?
The weighted average cost of capital represents the blended rate of return a company must earn to satisfy all capital providers — both debt holders and equity investors. It weights the cost of debt (after tax) and cost of equity by their proportions in the capital structure.
WACC is the discount rate used in DCF models to discount unlevered free cash flows to enterprise value.
What Is CAPM?
The Capital Asset Pricing Model estimates the expected return on equity — what shareholders require as compensation for bearing systematic risk. It takes three inputs: the risk-free rate, the stock’s beta (sensitivity to market movements), and the equity risk premium.
WACC vs CAPM: Side-by-Side Comparison
| Dimension | WACC | CAPM |
|---|---|---|
| What it measures | Blended cost of all capital (debt + equity) | Cost of equity only |
| Inputs | Cost of equity, cost of debt, tax rate, capital weights | Risk-free rate, beta, equity risk premium |
| Output | Single discount rate for the entire firm | Required return on equity |
| Scope | Firm-level | Equity-level |
| Relationship | Uses CAPM output as one of its inputs | Feeds into WACC calculation |
| Used in DCF | Yes — to discount unlevered FCF | Indirectly — through WACC |
| Accounts for debt | Yes — includes after-tax cost of debt | No — equity only |
| Tax benefit captured | Yes — debt tax shield included | No |
| Risk measure | Reflects overall capital risk | Reflects systematic risk via beta |
| Limitations | Assumes constant capital structure | Assumes markets are efficient, beta is stable |
How CAPM Feeds Into WACC
Here’s the relationship in plain terms: you need the cost of equity to calculate WACC. CAPM is the most common method to estimate that cost of equity. So the workflow is: CAPM → cost of equity → plug into WACC formula alongside cost of debt → get the discount rate for your DCF.
Alternatives to CAPM for estimating cost of equity include the Dividend Discount Model (DDM) build-up method and the Arbitrage Pricing Theory (APT), but CAPM remains the industry standard.
When to Use Each
Use CAPM when you need to estimate the required return on equity — for instance, when building a WACC or evaluating whether a stock’s expected return compensates for its risk. Use WACC when you need a discount rate for valuing an entire business, discounting project cash flows in capital budgeting, or comparing the return on invested capital (ROIC) against the cost of capital.
Key Takeaways
- CAPM estimates the cost of equity; WACC blends cost of equity and cost of debt into a single rate
- CAPM is an input to WACC — not a competing concept
- WACC is the discount rate for DCF models; CAPM drives the equity component of that rate
- Both rely on beta as a key risk measure, but WACC also incorporates leverage and tax effects
- Small changes in CAPM inputs (beta, ERP) have outsized impacts on WACC and valuation
Frequently Asked Questions
Is CAPM part of WACC?
Yes. CAPM provides the cost of equity estimate, which is one of the two main components of the WACC formula (the other being the after-tax cost of debt). CAPM feeds into WACC — they’re complementary, not competing tools.
Can you calculate WACC without CAPM?
Technically yes. You could estimate cost of equity using alternative methods like the Dividend Discount Model or a build-up approach. But CAPM is the most widely used method in practice, and most WACC calculations rely on it for the equity component.
What is a typical WACC?
For large, mature US companies, WACC typically ranges from 7–12%. Tech companies may have higher WACCs (10–15%) due to higher betas, while regulated utilities might have lower WACCs (5–8%) due to stable cash flows and significant debt capacity.
Why is beta so important in CAPM?
Beta is the only company-specific variable in CAPM. It measures how sensitive a stock is to market movements. A beta of 1.5 means the stock is 50% more volatile than the market. Higher beta → higher cost of equity → higher WACC → lower DCF valuation. Getting beta right matters enormously.
What are the main criticisms of CAPM?
CAPM assumes markets are perfectly efficient, investors are rational, and beta captures all relevant risk. In practice, none of these hold perfectly. Beta is unstable over time, CAPM ignores size and value premiums, and it doesn’t account for liquidity risk. Despite these flaws, it remains the standard framework because no alternative is both simpler and more accurate.