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CAPITAL ASSET PRICING MODEL
(CAPM)PRESENTED BYSIMRAN KAUR
CAPITAL ALLOCATION LINE Capital allocation line shows the reward to variability ratio in
terms of additional beta Let us denote a risk-free portfolio by F, a risky portfolio by M,
and a complete portfolio formed by combining them as C. Further w is the fraction of the overall portfolio invested in M, and the remaining (= 1-w) in F. The expected return of complete portfolio may be calculated as
E(+ w [ E(
TERMINOLOGY E( Expected rate of return on complete portfolio = Risk-free rate of return W = Fraction of complete portfolio C invested in risky asset
M E( = Expected return for risky asset M E(= Risk premium for risky asset E(Expected or required rate of return on asset i
STANDARD DEVIATION OF PORTFOLIO
Standard deviation of complete portfolio is given by
Where = standard deviation of complete portfolio Cw = fraction of complete portfolio C, invested in risky asset M = standard deviation of risky portfolio M
SEPARATION THEOREMA risk-averse investor assigns greater weight to the risk-free asset in his portfolio than an investor with greater risk tolerance. However, both use identical sets of two assets – one risk-free and another risky. This result is called separation theorem.
MARKET PORTFOLIOMarket portfolio is a theoretical construct credited to Prof. Eugene Fama. It is a huge portfolio that includes all traded assets in exactly the same proportion in which they are supplied in equilibrium. The return on market portfolio is the weighted average of return on all capital assets.
CAPITAL MARKET LINE (CML) CML is capital allocation line provided by one-month T-bills
as a risk-free asset and a market-index portfolio like Dow Jones, Standard and Poor’s and NYSE, as risky asset
It is one of the two elements of CAPM, the other being security market line (SML)
CML indicates - Locus of all efficient portfolios; Risk-return relationship and measure of risk for efficient portfolios; Relationship between risk (standard deviation) and expected return for efficient portfolio is linear; Appropriate measure of risk for portfolio is standard deviation of returns on portfolio
FUNCTIONS OF CML It depicts risk-return relationship for efficient portfolios
available to investors It shows the appropriate measure of risk for an efficient
portfolios is the standard deviation of return on portfolio
SECURITY MARKET LINE (SML) SML is a graphic depiction of CAPM and describes market
price of risk in capital markets E( Expected return = Risk-free return + (Beta * Risk premium of
market) On security i = Intercept + (Beta * Slope of SML) Risk premium on security I = Beta * Risk premium of market
CAPITAL ASSET PRICING MODEL (CAPM)
CAPM is an equilibrium model of trade-off between expected portfolio return and unavoidable (systematic) risk; the basic theory that links together risk and return of all assets
It is a logical and major extension of portfolio theory of Markowitz by William Sharpe, John Linterner and Jan Mossin
It provides framework for determining the equilibrium expected return for risky assets
IMPLICATIONS OF CAPM Risk-return relationship for an efficient portfolio Risk-return relationship for an individual asset/security Identification of under- and over-valued assets traded in the
market Effect of leverage on cost of equity Capital budgeting decisions and cost of capital Risk of firm through diversification of project portfolio
ASSUMPTIONS OF CAPM All investors are price-takers. Their number is so large that
no single investor can afford prices All investors use the mean-variance portfolio selection model
of Markowitz Assets/securities are perfectly divisible All investors plan for one identical holding period Homogeneity of expectation for all investors results in
identical efficient frontier and optimal portfolio Investors can lend or borrow at an identical risk-free rate There are no transaction costs and income taxes
EXPECTED RETURN IN CAPM Risk-free rate plus a premium for systematic risk based on
beta The premium of market portfolio, also referred to as reward,
depends on the level of risk-free return and return on market portfolio
Information related to the following 3 aspects are needed to apply CAPM: risk-free rate, risk premium on market portfolio and beta
RISK-FREE RATE Rate of return available on assets like T-bills, money market
funds or bank deposits is taken as proxy for risk-free rate The maturity period of T-bills and bank deposits is taken to
be less than one year, usually 364 days Such assets have very low or virtually negligible default risk
and interest rate risk
RISK-PREMIUM ON MARKET PORTFOLIO
It is the difference between the expected return on market portfolio and risk-free rate of return
CAPM holds that in equilibrium, the market portfolio is unanimously desirable risky portfolio
It contains all securities in exactly the same proportion in which they are supplied, that is, each security is held in proportion to its market value
It is an efficient portfolio, which entails neither lending nor borrowing
It is proportional to its risk (and degree of risk aversion of average investor
BETA It measures risk(volatility) of an individual asset relative to
market portfolio Assets with beta less than one are called defensive assets Assets with beta greater than one are called aggressive
assets Risk free assets have a beta equal to zero Beta is covariance of asset’s return with the market
portfolio’s return, divided by variance of market portfolio Beta of a portfolio is the weighted average of betas of assets
included in portfolio
CAPM EQUATION
Where = required rate of return on security j b = coefficient showing relative importance of beta
= beta of security jt = coefficient showing relative importance of tax effect = dividend yield on security j
POPULARITY OF CAPM Risk-return trade off – the direct proportional relationship
between the two – has a distinct intuitive appeal Transition from Capital Market Line (CML) to Security Market
Line (SML) shows that undiversifiable nature of the systematic risk makes it the relevant risk for pricing of securities and portfolios
Beta, the measure of systematic risk, is easy to compute and use
The model shows that investors are content to put their money in a limited number of portfolios, namely, a risk-free asset like T-bills and a risky asset like a market-index fund
PROBLEMS WITH CAPM One of this relates to the maturity of the risk-free asset,
namely, interest rate on a short term government security like a T-bill or a long-term rate like that on a treasury bond or an intermediate term-rate like that on a 3 year treasury securities
Whether market premium should be the expected or historical
Use of an appropriate market index If beta is appropriate risk measure
VARIABLES IN CAPM Taxes Inflation Liquidity Market capitalization size Price-earnings and market-to-book value ratios
ARBITRAGE PRICING THEORY (APT)
APT is based on concept of arbitrage It was developed in 1970 by Ross In the context of pricing of (return from) securities, arbitrage
implies finding/availability of two securities which are essentially the same (having different prices/returns)
APT has markets equilibrating across securities through arbitrage driving out mispricing
Arbitrage will ensure that riskless assets(or securities) provide the same expected return in competitive financial markets
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