Understanding the Capital Asset Pricing Model (CAPM): Key Concepts and Applications
This summary explores the Capital Asset Pricing Model (CAPM), an essential framework in modern finance. It outlines the model's foundational assumptions, such as investors being price takers and the existence of a market portfolio composed of all risky assets. The Security Market Line (SML), Black's Zero Beta Model, and the relationship between risk and return are detailed. Additionally, the model's equilibrium conditions highlight how risk premiums depend on individual securities' covariances with market returns. This analysis emphasizes CAPM's relevance in assessing investment risks and returns.
Understanding the Capital Asset Pricing Model (CAPM): Key Concepts and Applications
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Presentation Transcript
Chapter 7 The Capital Asset Pricing Model
Chapter Summary • Objective: To present the basic version of the model and its applicability. • Assumptions • Resulting Equilibrium Conditions • The Security Market Line (SML) • Black’s Zero Beta Model • CAPM and Liquidity
Capital Asset Pricing Model (CAPM) • Equilibrium model that underlies all modern financial theory • Derived using principles of diversification with simplified assumptions • Markowitz, Sharpe, Lintner and Mossin are researchers credited with its development
Assumptions • Individual investors are price takers • Single-period investment horizon • Investments are limited to traded financial assets • No taxes, and transaction costs
Assumptions (cont’d) • Information is costless and available to all investors • Investors are rational mean-variance optimizers • There are homogeneous expectations
Summary Reminder • Objective: To present the basic version of the model and its applicability. • Assumptions • Resulting Equilibrium Conditions • The Security Market Line (SML) • Black’s Zero Beta Model • CAPM and Liquidity
Resulting Equilibrium Conditions • All investors will hold the same portfolio of risky assets – market portfolio • Market portfolio contains all securities and the proportion of each security is its market value as a percentage of total market value • The market portfolio is on the efficient frontier and, moreover, it is the tangency portfolio
Resulting Equilibrium Conditions (cont’d) • Risk premium on the market depends on the average risk aversion of all market participants • Risk premium on an individual security is a function of its covariance with the market
E(r) CML M E(rM) rf m Capital Market Line
Slope and Market Risk Premium M = The market portfolio rf = Risk free rate E(rM) - rf = Market risk premium = Slope of the CML
Summary Reminder • Objective: To present the basic version of the model and its applicability. • Assumptions • Resulting Equilibrium Conditions • The Security Market Line (SML) • Black’s Zero Beta Model • CAPM and Liquidity
Expected Return and Risk on Individual Securities • The risk premium on individual securities is a function of the individual security’s contribution to the risk of the market portfolio • Individual security’s risk premium is a function of the covariance of returns with the assets that make up the market portfolio
E(r) SML E(rM) rf ß ß = 1.0 M Security Market Line
SML Relationships = Cov(ri,rm) / m2 Slope SML = E(rm) - rf = market risk premium E(r)SML = rf + [E(rm) - rf] BetaM = Cov (rM,rM) / sM2 = sM2 / sM2 = 1
Sample Calculations for SML E(rm) - rf = .08 rf = .03 a) x = 1.25 E(rx) = .03 + 1.25(.08) = .13 or 13% b) y = .6 E(ry) = .03 + .6(.08) = .078 or 7.8%
E(r) SML Rx=13% .08 Rm=11% Ry=7.8% 3% ß .6 1.0 1.25 ß ß ß y m x Graph of Sample Calculations
E(r) SML 15% Rm=11% rf=3% ß 1.25 1.0 Disequilibrium Example
Disequilibrium Example • Suppose a security with a of 1.25 is offering expected return of 15% • According to SML, it should be 13% • Under-priced: offering too high of a rate of return for its level of risk
Summary Reminder • Objective: To present the basic version of the model and its applicability. • Assumptions • Resulting Equilibrium Conditions • The Security Market Line (SML) • Black’s Zero Beta Model • CAPM and Liquidity
Black’s Zero Beta Model • Absence of a risk-free asset • Combinations of portfolios on the efficient frontier are efficient • All frontier portfolios have companion portfolios that are uncorrelated • Returns on individual assets can be expressed as linear combinations of efficient portfolios
E(r) Q P E[rz (Q)] Z(Q) Z(P) E[rz (P)] s Efficient Portfolios and Zero Companions
Zero Beta Market Model CAPM with E(rz (M)) replacing rf
Summary Reminder • Objective: To present the basic version of the model and its applicability. • Assumptions • Resulting Equilibrium Conditions • The Security Market Line (SML) • Black’s Zero Beta Model • CAPM and Liquidity
CAPM & Liquidity • Liquidity – cost or ease with which an asset can be sold • Illiquidity Premium • Research supports a premium for illiquidity • Amihud and Mendelson
CAPM with a Liquidity Premium f (ci) = liquidity premium for security i f (ci) increases at a decreasing rate
Average monthly return (%) Bid-ask spread (%) Illiquidity and Average Returns