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With investing, the higher the risk, the more an investor expects to earn. The capital asset pricing model (CAPM) tries to estimate how much you can expect to earn given the amount of risk. Investment professionals use the model in conjunction with fundamental, technical and other methods of securities analysis when making investment decisions. Of course, individuals with the know-how can use CAPM, too. Learn how to calculate it and how to use it to determine whether an investment is worth the risk.

Capital Asset Pricing Model (CAPM): The Basics 

The capital asset pricing model (CAPM) is widely used within the financial industry, especially for riskier investments. The model is based on the idea that investors should gain higher yields when investing in more high-risk investments, hence the presence of the market risk premium in the model’s formula.

Expected return = Risk-free rate  + (beta x market risk premium)

Using the capital asset pricing model, the expected return is what an investor can expect to earn on an investment over the life of that investment. It is a discount rate an investor can use in determining the value of an investment. The risk-free rate is the equivalent of the yield of a 10-year U.S government bond, though if the calculation is being done in another country, it should use that government’s 10-year bond yield.

Beta is the representation of a stock’s risk, a numerical value that quantifies how susceptible the stock is to changes in the market. If a stock’s risk outpaces the market, its beta is more than one. If its beta is less than one, it can reduce the risk within a diversified portfolio.

Lastly, the market risk premium represents an asset’s return beyond just the risk-free rate. The market risk premium is an added return that can entice investors to put capital into riskier investments.

Risky investments can be worthwhile to investors if the return rewards them for their time and risk tolerance. CAPM evaluates whether or not a stock’s value is worth that risk.

CAPM in Action

For example, say you’re looking at a stock worth $50 per share today that pays a 3% annual dividend. The stock’s beta is 1.5, making it riskier than the overall market. Also, assume that the risk-free rate is 3% and this investor expects the market to rise in value by 5% per year.

The expected return of the stock based on CAPM is 6%.


That expected return discounts the stock’s expected dividends and appreciation of the stock over the expected holding period. If the discounted value of future cash flows is equal to $50, CAPM says the stock has a fair price for its risk.

History of CAPM

William Sharpe, an economist and Nobel Laureate devised CAPM for his 1970 book Portfolio Theory and Capital Markets. He notes that an individual investment contains two kinds of risk:

  • Systematic Risk: In other words, market risk that portfolio diversification can’t reduce. Interest rates, recessions, and wars are examples of systematic risks.
  • Unsystematic Risk: This “specific risk” relates to a specific company or industry. Strikes, mismanagement or shortage of a necessary component in the manufacturing process all qualify as unsystematic risk.

Pros and Cons of CAPM

The capital asset pricing model is important in the world of financial modeling for a few key reasons. Firstly, by helping investors calculate the expected return on an investment, it helps determine how appropriate a particular investment may be. Investors can use the CAPM for gauging their portfolio’s health and rebalancing, if necessary.

Secondly, it’s a relatively simple formula that’s fairly easy to use. Additionally, the CAPM is an important tool for investors when it comes to accessing both risk and reward. It’s also one of the few formulas that accounts for systematic risk.

That said, CAPM’s critics say it makes unrealistic assumptions. For instance, beta doesn’t acknowledge that price swings in either direction don’t hold equal risk. Also, using a particular period for risk assessment ignores that risk and returns don’t distribute evenly over time.

Also, the CAPM assumes a constant risk-free rate, which isn’t always the case. A 1% bump in treasury bond interest rates would significantly affect that investment. Meanwhile, using a stock index like the S&P 500 only suggests a theoretical value. That index could perform differently over time.

The Bottom Line


While the capital asset pricing model isn’t without its downfalls, it remains a key tool for investment decision-making. The CAPM helps determine whether an investment is worth the risk.

The potential upsides of the CAPM include ease of use and calculating a riskier investment’s rate of return. However, critics say the CAPM carries loads of inaccurate assumptions. It isn’t perfect, but CAPM still can be a useful tool for assessing risk.

Investing Tips

  • If you want to reduce the risk in your portfolio, a financial advisor can help. To find the right one for you, use SmartAsset’s free tool. It will connect you with up to three advisors in your area. If you’re ready to be matched with local advisors that will help you achieve your financial goals, get started now.
  • Have you figured out how much investment risk you’re willing to take on? Do you know how much your investment needs to grow to reach your goals? Did you look into how much inflation and capital gains tax will take out of your investment? SmartAsset’s investing guide can help you figure out these key first steps toward successful investing.

Photo credit: ©iStock.com/NicolasMcComber, ©iStock.com/Ong-ad Nuseewor, ©iStock.com/stevecoleimages

Rachel Cautero Rachel Cautero writes on all things personal finance, from retirement savings tips to monetary policy, even how young families can best manage the financial challenges of having children. Her work has appeared in The Atlantic, Forbes, The Balance, LearnVest, SmartAsset, HerMoney, DailyWorth, The New York Observer, MarketWatch, Lifewire, The Local: East Village, a New York Times publication and The New York Daily News. Rachel was an Experian #CreditChat panelist and has appeared on Cheddar Life and NPR’s On Point Radio with Meghna Chakrabarti. She has a bachelor’s degree from Wittenberg University and a master's in journalism from New York University. Her coworkers include her one-year-old son and a very needy French bulldog.
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