FNCE 625 – Investment Analysis and Management
Investments: Analysis and Management
Fourteenth Edition
Gerald R. Jensen and Charles P. Jones
Chapter 9
Capital Market Theory and Asset Pricing Models
Capital Asset Pricing Model 1
Positive rather than normative
It is objective and fact-based, not subjective or opinion-based
Focus on the equilibrium relationship between the risk and expected return on risky assets
Builds on Markowitz portfolio theory
Each investor is assumed to diversify his or her portfolio according to the Markowitz model
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Capital Asset Pricing Model 2
Assumes all investors:
Use the same information to generate an efficient frontier
Have the same one-period time horizon
Can borrow or lend money at the risk-free return
No transaction costs, no income taxes, no inflation
No single investor can affect the price of a stock
Capital markets are in equilibrium
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Risk-Free Asset, Borrowing, Lending
Risk free asset
No correlation with risky assets
Usually proxied by a Treasury security
Adding a risk-free asset extends and changes the efficient frontier
Risk-free investing is “lending” because investor lends money to issuer
With borrowing, investor no longer restricted to personal wealth
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Risk-Free Lending/Borrowing
Risk-free asset combined with port. T (T is part of efficient set AB)
RF to T: lending portfolios
T to L: borrowing portfolios
Portfolios on line R F to L dominate all portfolios below (e.g., Z and X)
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The New Efficient Set
Risk-free investing and borrowing creates a new set of risk-expected return possibilities
Addition of risk-free asset results in:
A change in the efficient set from an arc to a straight line tangent to the original frontier
Chosen (optimal) portfolio depends on investor’s risk-return preferences
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Capital Market Line 1
Line from RF to L is capital market line (CML)
x = risk premium = E(RM) − RF
y-intercept = RF
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Capital Market Line 2
Slope of C M L is the market price of risk for efficient portfolios, or the equilibrium price of risk in the market
Relationship between risk and expected return for portfolio P (Equation for C M L):
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Market Portfolio
Most important implications of C M L
The portfolio of all risky assets is the optimal risky portfolio (called the market portfolio)
The expected price of risk is always positive
The optimal portfolio is at the highest point of tangency between R F and efficient frontier
All investors hold the same optimal portfolio of risky assets
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Characteristics of Market Portfolio
All risky assets must be in portfolio, so it is completely diversified
Includes only systematic risk
Unobservable but approximated with portfolio of all common stocks
In turn, approximated with S and P 500
All securities included in proportion to their market value
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The Separation Theorem
Investors use their preferences (indifference curves) to determine optimal portfolio
Separation Theorem
The investment decision about which risky portfolio to hold is separate from the financing decision
Investment decision does not involve investor
Financing decision depends on investor’s preferences
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Remaining Questions Not Addressed by CML
How do you determine the expected return for individual securities or undiversified portfolios?
How do investors determine the risk a security will add to their portfolio?
* Solution is achieved by assuming investors hold well-diversified portfolios
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Security Market Line
C M L only applies to markets in equilibrium and efficient portfolios
The security market line (S M L) depicts tradeoff between risk and expected return for individual securities and portfolios
Under C A P M, all investors hold the market portfolio
Relevant risk of any security is, therefore, its covariance with the market portfolio
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Beta – What does it tell us?
Standardized measure of systematic risk
Relative measure of risk: risk of an individual stock relative to the market portfolio of all assets
Relates an asset’s covariance with the market portfolio to the variance of the market portfolio
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Beta (β) – What is it?
Risk an asset will add to a well-diversified portfolio
Measures an asset's nondiversifiable risk
Slope of the line formed when an asset’s returns are regressed against the market return
Measure of the sensitivity of an asset’s returns to changes in the market return
The relevant risk measure for well-diversified investors
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Beta Characteristics
Beta > 1; security moves with the market, only more; security is riskier than average
0 < Beta < 1; security moves with the market, only less
Beta < 0; security moves counter to the market
Market beta equals 1
Portfolio beta is a weighted average of individual stock betas
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Betas of Selected Companies
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| Company | Beta |
| Amazon | 1.35 |
| McDonald’s | 0.72 |
| Kellogg Company | 0.64 |
| Bristol- Myers Squibb | 0.80 |
| Walmart | 0.87 |
| FirstEnergy | 0.50 |
| Conoco Philips | 0.74 |
| Delta Air Lines | 1.29 |
| Goldman Sachs | 1.35 |
| Barrick Gold | 0.32 |
| FedEx | 1.31 |
C A P M’s Expected Return-Beta Relationship
Required return on asset (ki) is composed of:
Risk-free rate (RF )
Risk premium
The greater the systematic risk, the greater the required return
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Beta and the SML/CAPM
Beta = 1.0; equal risk to market (average)
Securities A and B are more risky than the market
Beta > 1.0
Security C is less risky than the market
Beta < 1.0
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Estimating the S M L
Treasury bond rate used to estimate R F
Expected market return unobservable
Often estimated using past market returns and taking a mean value
Estimating security betas is difficult
Beta is only company-specific factor in C A P M
Beta estimation requires asset-specific forecast
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SML and Under(Over)-Valued Assets
Securities ABC and XYZ are undervalued
Security L M N is overvalued
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C A P M/S M L Implications
Higher risk assets require higher returns
Investors are only compensated for bearing non-diversifiable risk
Asset prices are not impacted by diversifiable risk
Undiversified investors have an inferior risk-expected return trade-off
Investors determine the risk they bear; market determines their compensation
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Estimating Beta
Market model
Relates a stock’s return to the return on the market, assumes a linear relationship
Produces an estimate of return for any stock
Characteristic line
Line fit to a security’s return relative to the market index
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Amazon’s Characteristic Line
Slope = rise ÷ run = Beta
Is AMZN’s beta > 1?
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How Accurate Are Beta Estimates? 1
Betas change with a company’s situation
Estimating a future beta
May differ from the historical beta
RM represents the total of all marketable assets in the economy
Approximated with a stock market index
Approximates return on all common stocks
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How Accurate Are Beta Estimates? 2
Methods for estimating beta vary by time period, market index, return interval, etc.
Therefore, estimates of beta vary
Regression estimates of true
from the
characteristic line are subject to error
Portfolio betas are more reliable than individual security betas
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Tests of C A P M
Assumptions are mostly unrealistic
Empirical evidence has not led to consensus
Points widely agreed upon
S M L (C A P M) appears to be linear
Intercept is generally higher than R F
Slope of S M L is generally less than theory predicts
It is likely that only systematic risk is rewarded
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Arbitrage Pricing Theory
Based on Law of One Price
Two assets with identical future cash flow streams cannot sell at different prices
Equilibrium prices adjust to eliminate all arbitrage opportunities
Unlike C A P M, A P T does not assume
Single-period investment horizon, absence of taxes, riskless borrowing or lending, mean-variance decisions
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Factors
A P T assumes returns generated by a factor model that allows for more than 1 factor
Factor Characteristics
Each risk must have a pervasive influence on stock returns
Risk factors must influence expected return and have non-zero prices
Risk factors must be unpredictable to the market
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A P T Model
Most important - the deviations of the factors from their expected values
Expected return is directly related to sensitivity
C A P M assumes only risk is sensitivity to market
Expected return-risk relationship for the A P T can be described as:
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Problems with A P T
Risk factors are not specified ex ante
To implement A P T model, need factors that account for differences in security returns
C A P M identifies market portfolio as single factor
Studies suggest certain factors are reflected in security returns
Both C A P M and A P T rely on unobservable expectations
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Copyright
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