Pitfalls And Accuracy Of Capital Asset Pricing Model Finance Essay

Pitfalls And Accuracy Of Capital Asset Pricing Model Finance Essay

The Capital Asset Pricing Model ( CAPM ) was the work of William Sharpe ( 1964 ) and John Lintner ( 1965 ) ( Fama & A ; French, 2004 ) . It is used to happen the cost of capital for houses and measure the public presentation of portfolios. It helps in mensurating the hazard, and happening the expected return on the portfolio. Two types of hazard are involved in the investing portfolios: systematic hazard and non-systematic hazard. Non-systematic hazard is specific to single stocks, and it can be diversified by increasing the figure of stocks in one ‘s portfolio. Systematic hazard, nevertheless, can non be diversified, because it includes the market hazards, like alteration in involvement rates, wars, etc. The CAPM is used to mensurate this systematic hazard, and its consequence on the expected rate of return.

In the capital plus pricing theoretical account, the hazard associated with an plus is measured in relationship to the hazard of the market as a whole. This is expressed as the stock ‘s a ( beta ) , or correlativity to the market norm. The returns of an plus will, on norm, move every bit with the returns of the overall market. Assetss with I? & lt ; I will expose mean motions in return less utmost than the overall market, while those with a & gt ; I will demo return fluctuations greater than the overall market ( Cooper, Encyclopedia of Business, 2nd edition ) .

Ks = Krf + B ( Km – Krf ) ( McCracken, 2009 )

Ks = The Required Rate of Return, ( or merely the rate of return ) .

Krf = The Risk Free Rate ( the rate of return on a “ hazard free investing ” , like U.S. Government Treasury Bonds )

B = Beta

Km = The expected return on the overall stock market.

Pitfalls of CAPM

The CAPM has been criticized for its unrealistic premises. First, it assumes that a perfect capital market exists, intending that the capital market is in perfect equilibrium and the demand for securities from the risk-averse investors matches the available supply. This, nevertheless, is non the instance in world because in the existent universe the investing determinations are made by companies and persons. By presuming that the markets are perfect, this theoretical account ignores the effects of revenue enhancements, rising prices, dealing costs, and short merchandising on the capital markets.

This theoretical account besides assumes that perfect information is freely available to all investors, as a consequence of which they all have same outlooks ( homogeneous outlooks ) about plus returns- that they agree about mean and discrepancy as the lone system of market appraisal. This may non be true, because in the existent market non all the information is available to the investors ; besides, non all the investors have the same outlooks about hazard and return. Even though, harmonizing to the CAPM, the investors might prefer lower hazard to higher hazard at a specified return, and a higher return to lower return at a specific degree of hazard, there could be those who accept lower returns at a high degree of hazard ( McCracken, 2009 ) . The theoretical account does non take the 3rd type into consideration.

The CAPM theoretical account assumes that there is a positive linear relationship between the return on portfolio and the beta of the portfolio ; and the difference in assets ‘ expected returns is merely because their betas are different. However, surveies carried out by some professors ( Eugene Fama and Kenneth French ) suggest that between 1963 and 1990 there were times when the stock public presentation could non be explained by the differences in betas ( McClure, 2006 ) . Besides, there were periods when there was no additive relationship between the beta and the single stock returns. These findings suggest the hapless building of the CAPM theoretical account.

CAPM could merely be applied to those portfolios that have been diversified because it assumes that the investors hold diversified portfolios. This means that the CAPM merely provides the needed return for the systematic hazard of the investors ‘ portfolios. Hence CAPM can non be applied to the portfolios that are non diversified.

Another serious job is that this theoretical account assumes that loaning and adoption can take topographic point at riskless rates ( for which the output on short-run Government debt is taken as a placeholder ) . In world this is non possible, because the hazard associated with single investors is much higher than that associated with the Government, so the investors can non borrow at the riskless rate. This means that the incline of the security market line ( SML ) is shallower in pattern than in theory. SML shows the relationship between the return and the hazard. Another job associated with utilizing output on short-run Government debt as the riskless rate of return is that this output keeps altering on a day-to-day footing depending on the economic state of affairs. Same is the instance with the beta values that alteration with clip and make non stay changeless. This gives rise to uncertainness in the value of the expected return. Since the CAPM considers beta to be the most of import factor for the alteration in the expected returns of the assets, frequent alterations in the beta might take to inaccurate consequences.

Problems could besides originate when the CAPM is used to cipher a project-specific price reduction rate. This job is specially seen in the placeholder companies that undertake more than one concern activity. It is hard to happen one suited placeholder beta for such a company. Proxy beta is used when the company is non listed in the market and therefore has no beta of its ain. It is taken from a comparable listed company and adjusted as necessary for comparative fiscal geartrain degrees, therefore proxy price reduction rates ( London South East, lse.co.uk ) .

Problem with this proxy beta for a certain investing undertaking is that it must be separated from the company ‘s equity beta. For this the market value of the proxy company should be viewed, and the betas of the several different countries of the proxy company should be averaged to obtain the equity beta. This, nevertheless, may take to inaccurate consequences as the information about comparative portions of the proxy company market value may be rather hard to obtain. Besides, the companies holding complicated capital constructions find it hard to acquire information to acquire their betas. The CAPM assumes a standard keeping period to compare the returns on different securities. Therefore, a security acquiring a return over six months can non be compared with the security acquiring a return over 12 months. Keeping all this in head, a job in utilizing the CAPM in investing assessment is that the above mentioned instance involves multi-period investing assessment, whereas CAPM assumes a single-period clip skyline.

How the CAPM was Considered to be Accurate

The CAPM was considered better and accurate than other methods of ciphering needed return due to the undermentioned grounds:

It is simple and reasonable since it is based on the modern portfolio theory harmonizing to which the investors should diversify to extinguish non-systematic hazard, they should keep merely the riskless plus and the market portfolio, and an plus ‘s systematic hazard is measured by part to the hazard of the market portfolio. Besides, it provides a simple pricing theoretical account, and is comparatively easy to implement.

It considers systematic hazard merely, and in world most of the investors have diversified portfolios and have eliminated non-systematic hazard from their portfolios. Besides, it is considered to be better than other theoretical accounts, like the Dividend Growth Model ( DGM ) for the computation of the cost of equity, and Weighted Average Cost of Capital ( WACC ) for ciphering the price reduction rates.

Diagrammatically, return-beta relationship through the security market line or the SML can be represented as shown in the graph below.

Beginning: hypertext transfer protocol: //economics.fundamentalfinance.com/capm.php In equilibrium, all assets will lie on the SML because they will hold an appropriate return-beta relationship. However, if we depart from equilibrium some assets will non be right priced. If an plus is overpriced it will lie below the SML since it will supply an expected return less than what is determined by the SML given its hazard ( beta ) . If an plus is underpriced it will lie above the SML since its return will be greater than what the SML determines ( Taylor, 2005 ) . This will assist the investors in doing determinations of whether they should keep low-beta or high-beta stocks. For illustration, if the market falls, the investors will prefer keeping low-beta stocks. They can besides custom-make their portfolio to their specific risk-return demands. So when the market is lifting, they will keep securities holding a beta greater than one ; when the market falls, they will keep securities with a beta less than one.

The message conveyed by the CAPM, that by taking a higher hazard the investors will gain a higher return, resulted in the rise in the usage of indexing – piecing a portfolio of portions to mime a peculiar market – by risk-averse investors ( McClure, 2006 ) .

The CAPM non every bit Accurate as Claimed

Fama and French, in the trials that they carried out, found that the CAPM does non give an accurate value of the needed returns. Reasons were the premises of the theoretical account, most of which, as already discussed, were unrealistic and did non be in the real-world conditions. They found that while the CAPM ‘s step of systematic hazard was undependable, steadfast size and book-to-market ratios were more reliable ( Taylor, 2005 ) .

Harmonizing to Roll ( 1977 ) , the CAPM is inaccurate because it has ne’er been tested, and the market portfolio on which this theoretical account is based is theoretically and through empirical observation ill-defined ( Fama & A ; French, 2004 ) . It is non theoretically clear which assets can truly be excluded from the market portfolio, and those assets that are included, informations about them is non sufficient. So the CAPM is tested utilizing the placeholders for the market portfolio and non the true market portfolio, and the placeholders are frequently unequal, and this may give rise to a prejudice in gauging the house ‘s cost of equity.

A major job for the CAPM is that portfolios that are formed by screening stocks on monetary value ratios produce different norm returns which are non positively related to the market betas ( Fama & A ; French, 2004 ) . Besides, harmonizing to Fama and French, the CAPM consequences in a really high cost of capital for high-beta stocks ( when compared with the historical norm returns ) , and it provides really low costs of capital for the low-beta stocks.

There are likely to be mistakes in finding a most-correlated plus. CAPM, because of the mistakes in the definition of the optimum portfolio and mistakes in beta, would probably give an wrong monetary value. Even if the most correlative plus is right identified, it is of import to gauge the needed statistics- the means, carbon monoxide discrepancies, and variances- called for in the corresponding pricing expression.


The CAPM is used to happen the cost of capital of the portfolios, and to measure their public presentation. It is based on the modern market portfolio, which makes it simple and easy to be implemented ; it is considered better than the Dividend Growth Model and the WACC ; it clearly identifies the relationship between the returns and the beta, which is positively additive, which helps the investors make determinations about what sort of stocks should they put in, high-beta or low-beta. Despite of its utility, this theoretical account is non considered as accurate by many of the research workers, because its premises are considered to be unrealistic. It assumes that a perfect capital market exists, and that it is in equilibrium ; harmonizing to this theoretical account, loaning and adoption can take topographic point at the riskless rates, which is non realistic ; perfect information is freely available to all the investors due to which they have homogeneous outlooks about the plus returns. Some surveies that were carried out negate the positive linear relationship between the returns and hazard. Problems besides arise when the CAPM is used for investing assessment. It was besides found out that the CAPM gives unrealistic values of the needed returns, which are higher than the historical norm returns for the high- beta stocks, and lower for the low-beta stocks. Hence, looking at the above findings, we can reason that even though the CAPM is widely used today, it is non an accurate theoretical account.