What is the cost of equity in simple terms?

It's the return shareholders expect for taking the risk of owning a company's stock instead of holding a safe asset. Unlike interest on a loan, it isn't stated anywhere — it has to be estimated, usually with CAPM.

How do you calculate the cost of equity?

The most common method is CAPM: take the risk-free rate, add the equity risk premium multiplied by the stock's beta. The result is the expected return that compensates shareholders for their risk.

What does a high beta mean for the cost of equity?

A higher beta means the stock is more volatile relative to the market, so investors demand a bigger risk premium. That pushes the cost of equity — and the company's WACC — higher.

Is cost of equity the same as WACC?

No. Cost of equity covers only the shareholders' required return. WACC blends the cost of equity with the cost of debt, weighted by how much of each the company uses.

Where do I find a company's beta?

Beta is published on most financial data sites and brokerage platforms, calculated from historical price movements. Because providers use different time periods, you'll sometimes see slightly different betas for the same stock.

Cost of Equity Explained: How CAPM and Beta Actually Work

The cost of equity is the return your shareholders demand for their risk. Here's the CAPM formula, what beta really means, and a worked example.

When a company raises money by selling shares, that money isn't free. Shareholders take on risk, and in return they expect a certain rate of return. That expected return is the cost of equity — and it's usually the single biggest ingredient in a company's <a href="/blog/what-is-wacc-complete-guide">WACC</a>.

The tricky part is that, unlike a loan with a stated interest rate, the cost of equity is never written down anywhere. You have to estimate it. The standard tool for doing that is the Capital Asset Pricing Model, or CAPM. This article explains CAPM in plain terms, shows what beta really measures, and works through an example you can follow.

The idea behind the cost of equity

Think about what a shareholder is giving up. They could put their money in a completely safe place — a government bond — and earn a modest, near-guaranteed return. By buying a stock instead, they're accepting the risk that the price falls. They will only do that if they expect to be paid extra for taking on that risk. So the cost of equity has two parts: the safe return they could have had anyway, plus a premium for the risk of this particular stock. CAPM is just a formula that puts numbers on those two parts.

The CAPM formula

Cost of equity (Re) = Rf + β × (Rm − Rf)

The pieces: Rf is the risk-free rate, the return on a "safe" asset, usually a long-dated government bond such as the 10-year Treasury — the baseline every investor could earn without taking equity risk. (Rm − Rf) is the equity risk premium, the extra return investors have historically demanded for holding stocks over bonds, typically estimated somewhere around 4.5–5.5% based on long-run market history. β (beta) is the stock's sensitivity to the market, the multiplier that scales the risk premium up or down for one specific company. In words: start with the safe return, then add a risk premium that's scaled by how risky this particular stock is relative to the market.

What beta really means

Beta is the part people misunderstand, so it's worth slowing down. Beta measures how much a stock tends to move when the overall market moves. A beta of 1.0 means the stock moves roughly in line with the market. A beta of 1.5 means that when the market rises or falls 10%, this stock tends to move about 15% — more volatile, more risk, higher cost of equity. A beta of 0.6 means the stock moves only about 6% for every 10% market move — more defensive, lower cost of equity. A utility company with stable demand might have a beta well below 1, while a high-growth technology stock might have a beta above 1.5. Because beta gets multiplied by the risk premium, even a modest change in beta can move the cost of equity — and therefore the whole WACC — by a meaningful amount.

A worked example

Let's estimate the cost of equity for our fictional TechCo. (Rates are illustrative; use current market figures when you do this for real.) With a risk-free rate (Rf) of 4.0%, a beta (β) of 1.20, and an equity risk premium (Rm − Rf) of 5.0%, the calculation is Re = 4.0% + (1.20 × 5.0%) = 4.0% + 6.0% = 10.0%. So shareholders in TechCo are, in effect, demanding about a 10% annual return for the risk they're carrying. Notice how much beta drives this: if TechCo's beta were 1.5 instead of 1.2, the cost of equity would jump to 4.0% + (1.5 × 5.0%) = 11.5%.

How this feeds into WACC

The cost of equity rarely travels alone. It's one of the two prices blended together to form a company's overall funding cost. In the <a href="/blog/what-is-wacc-complete-guide">WACC formula</a>, the cost of equity is weighted by the share of funding that comes from shareholders, then added to the after-tax cost of debt. Because equity is usually the larger slice, the cost of equity tends to dominate the final WACC — which is why getting beta and the risk premium sensible matters so much. You can see exactly how a change in the cost of equity flows through to WACC using the <a href="/financial-tools/wacc-calculator">WACC calculator</a>: adjust the beta input and watch the final rate respond.

Open WACC Calculator

Practical cautions

A few cautions are worth keeping in mind. Beta is backward-looking — it's measured from past price movements, which may not reflect future risk, so many investors sanity-check it against the company's business rather than trusting the number blindly. The risk-free rate moves: when bond yields change, every cost of equity changes with them, so a figure from last year may be stale. And the equity risk premium is an estimate, not a fact — reasonable analysts use slightly different numbers, and small differences here ripple through your valuation. Treat the cost of equity as a careful estimate, test it with a range of inputs, and you'll have a far more honest picture of what a stock is worth. From here, the natural next step is seeing how WACC turns into an actual valuation in <a href="/blog/wacc-discount-rate-dcf-valuation">how to use WACC as a discount rate</a>.