Risk—A Preliminary Definition A preliminary definition of investment risk is the probability that return will be less than expected Feelings About Risk – Most people have negative feelin
Trang 1Chapter 9 Risk and Return
Trang 2Why Study Risk and Return ?
Is there a way to invest in stocks to take advantage of the high returns while minimizing the risks?
Investing in portfolios enables investors to manage and control risk while receiving high returns.
– A portfolio is a collection of financial assets
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Trang 3The General Relationship Between
Risk and Return
Risk – The meaning in everyday language: The probability of losing some or all of the money invested
Understanding the risk-return relationship involves:
– Define risk in a measurable way
– Relate that measurement to a return
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Trang 4Portfolio Theory—Modern Thinking about Risk and Return
Portfolio theory defines investment risk in a measurable way and relates it to the expected level of return from an investment
– Major impact on practical investing activities
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Trang 5The Return on an Investment
The rate of return allows an investment's return to be compared with other investments
One-Year Investments
– The return on a debt investment is
k = interest paid / loan amount
– The return on a stock investment is
k = [D1 + (P1 – P0)] / P0
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Trang 6The Expected Return
The expected return on stock is the return investors feel is most likely
to occur based on current information
– Anticipated return based on the dividends expected as well as the future expected price
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Trang 7The Required Return
The required return on a stock is the minimum rate at which investors will purchase or hold a stock based on their perceptions of its risk
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Trang 8Risk—A Preliminary Definition
A preliminary definition of investment risk is the probability that return will be less than expected
Feelings About Risk
– Most people have negative feelings about bearing risk: Risk Aversion
– Most people see a trade-off between risk and return
– Higher risk investments must offer higher expected returns to be acceptable
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Trang 9Review of the Concept of a
Random Variable
In statistics, a random variable is the outcome of a chance process and has a probability distribution
– Discrete variables can take only specific variables
– Continuous variables can take any value within a specified range
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Trang 10Review of the Concept of a
Random Variable
The Mean or Expected Value
– The most likely outcome for the random variable
For symmetrical probability distributions, the mean is the center of the distribution
Statistically it is the weighted average of all possible outcomes
Trang 11Review of the Concept of a
Random Variable
Variance and Standard Deviation
– Variability relates to how far a typical observation of the variable is likely to deviate from the mean
– The standard deviation gives an indication of how far from the mean a typical observation is likely to fall
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Trang 12Review of the Concept of a
Trang 13Concept Connection Example 9-1 Discrete Probability Distributions
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1.0000
0.0625 4
0.2500 3
0.3750 2
0.2500 1
0.0625 0
P(X) X
The mean of this distribution is 2, since it is a
symmetrical distribution.
If you toss a coin four times, what is the chance of getting x heads?
Trang 14Figure 9-1 Discrete Probability Distribution
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Trang 15Concept Connection Example 9-2
Calculating the Mean of a Discrete Distribution
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Trang 16Concept Connection Example 9-3 Variance and Standard Deviation
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Trang 17Review of the Concept of a
Random Variable
The Coefficient of Variation
– A relative measure of variation — the ratio of the standard deviation of a distribution to its mean
CV = Standard Deviation ÷ Mean
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X
Trang 18Review of the Concept of a
Random Variable
Continuous Random Variable
– Can take on any numerical value within some range
– The probability of an actual outcome involves falling within a range of values rather than being an exact amount
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Trang 19Figure 9-2 Probability Distribution for a Continuous Random Variable
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Trang 20The Return on a Stock Investment as a Random Variable
Return is influenced by stock price and dividends
Return is a continuous random variable
The mean of the distribution of returns is the expected return
The variance and standard deviation show how likely an actual return will be some distance from the expected value
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Trang 21Figure 9-3 Probability Distribution of the Return on an Investment in
Stock X
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Trang 22Figure 9-4 Probability Distributions With Large and Small Variances
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Trang 23Risk Redefined as Variability
In portfolio theory, risk is variability as measured by variance or standard deviation
A risky stock has a high probability of earning a return that differs significantly from the mean
of the distribution
A low-risk stock is more likely to earn a return similar to the expected return
In practical terms risk is the probability that return will be less than expected
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Trang 24Figure 9-5 Investment Risk Viewed as Variability of Return Over Time
Trang 25Risk Aversion
Risk aversion means investors prefer lower risk when expected returns are equal
When expected returns are not equal the choice of investment
depends on the investor's tolerance for risk
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Trang 26Figure 9-6 Risk Aversion
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Trang 27Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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Harold will invest in one of two companies:
Evanston Water Inc (a public utility)
Astro Tech Corp (a high-tech company).
Public utilities are low-risk - regulated monopolies
High tech firms are high-risk - new ideas can be very successful or fail completely
Harold has made a discrete estimate of the probability distribution of returns for each stock:
Trang 28Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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Evaluate Harold's options in terms of the statistical concepts of risk and return
Trang 29Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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First calculate the expected return for each stock.
Next calculate the variance and standard deviation of the return on each stock:
Trang 30Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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Trang 31Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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Finally, calculate the coefficient of variation for each stock’s return.
Trang 32Example 9-4 Discussion
Which stock should Harold choose
– Astro is better on expected return but Evanston wins on risk
Consider
– Worst cases and Best cases
– How variable is each return around its mean
– Does a picture (next slide) help?
– Which would you choose
Is it likely that Harold’s choice would be influenced by his age and/or wealth?
Trang 33Concept Connection Example 9-4 Evaluating Stand-Alone Risk
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Continuous approximations of the two distributions are plotted as follows:
Trang 34Decomposing Risk—Systematic and Unsystematic Risk
Movement in Return as Risk
– Total up and down movement in a stock's return is the total risk inherent in the stock
Separate Movement/Risk into Two Parts
– Market (systematic) risk
– Business-specific (unsystematic) risk
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Trang 35Defining Market and Business-Specific Risk
Risk is Movement in Return
Trang 36A portfolio is the collection of investment assets held by an investor
Portfolios have their own risks and returns
A portfolio’s return is simply the weighted average of the returns of the stocks in it
– Easy to calculate
A portfolio’s risk is the standard deviation of the probability distribution of its return
– Depends on risks of stocks in portfolio, but
– Very complex and difficult to calculate/measure
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Trang 37Goal of the Investor/Portfolio Owner is to capture the high average returns
of stocks while avoiding as much of their risk as possible
Investors are concerned only with how stocks impact portfolio
performance,
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Trang 38Diversification—How Portfolio Risk Is Affected When Stocks Are
Added
Diversification - adding different (diverse) stocks to a portfolio
Business-Specific Risk and Diversification
– Business Specific risk: Random events
– Good and Bad effects wash out in large portfolio
Business-Specific Risk is said to be “Diversified Away” in a well-diversified portfolio –
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Trang 39Diversifying to Reduce Market (Systematic) Risk
Market risk is caused by events that affect all stocks
move together
Not perfectly positively correlated with the market
individual returns (next slide)
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Trang 40Figure 9-7 Risk In and Out of a Portfolio
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Trang 41Portfolio Theory and the Small Investor
The Importance of Market Risk
Large, diversified portfolio
For the small investor with a limited portfolio the theory’s results may not apply
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Trang 42Measuring Market Risk The Concept of Beta
Market risk is crucial
– It’s all that’s left because Business-Specific risk is diversified away
– The theory needs a way to measure market risk for individual stocks
In the financial world, a stock’s “Beta” is a widely accepted measure of its risk
– Beta measures the variation in a stock’s return that accompanies variation in the market's return
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Trang 43Measuring Market Risk The Concept of Beta
Developing Beta
– Determine the historical relationship between a stock's return and the return on the market
Regress stock’s return against return on an index such as the S&P 500
Projecting Returns with Beta
– Knowing a stock's Beta enables us to estimate changes in its return given
changes in the market's return
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Trang 44Figure 9-8 The Determination of Beta
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Trang 45Concept Connection Example 9-6 Projecting Returns with Beta Conroy’s beta is 1.8 It’s stock returns 14% The market is declining, and experts estimate the return on an average stock will fall by 4% from 12% to 8% What is Conroy’s new return likely to be?
Solution:
Beta represents the past average change in Conroy’s return relative to changes in the market’s return.
The new return can be estimated as
kConroy = 14% - 7.2% = 6.8%
Conroy Conroy Conroy
M Conroy
Trang 46Measuring Market Risk The Concept of Beta
Betas are developed from historical data
environment has occurred
Beta for a Portfolio
portfolio
Weighted by $ invested
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Trang 47Using Beta The Capital Asset Pricing Model CAPM)
CAPM attempts to explain how stock prices are set
CAPM's Approach
– People won't invest in a stock unless its expected return is at least equal to their required return for that stock
– CAPM attempts to quantify how required returns are determined
– The stock’s value (price) is estimated based on CAPM’s required return for that stock
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Trang 48Using Beta The Capital Asset Pricing Model (CAPM)
Rates of Return, The Risk-Free Rate and Risk Premiums
– The current return on the market is kM
– The risk-free rate (kRF) –
no chance of receiving less than expected
Investing in any other asset is risky
– Investors require a “risk premium” of additional return over kRF when there is risk
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Trang 49The CAPM’s Security Market Line (SML)
The SML proposes that required rates of return are determined by:
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The Market Risk Premium is (kM – kRF)
The Risk Premium for Stock X
The beta for Stock X times the market risk premium
In the CAPM a stock’s risk premium is determined only by the stock's market risk as measured by its beta
Market Risk Premium Stock X's Risk Premium
k = k + 1 4 2 4 3 k k − b
1 4 4 2 4 43
Trang 50Figure 9-9 The Security Market Line
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Trang 51The Security Market Line (SML)
Valuation Using Risk-Return
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Trang 52Concept Connection Example 9-10 Valuing (Pricing) a Stock with CAPM
Kelvin paid an annual dividend of $1.50 recently, and is expected to grow at 7% indefinitely
T- bills yield 6%, an average stock yields 10%
Kelvin is a volatile stock Its return moves about twice as much as the average stock in response to political and economic changes
What should Kelvin sell for today?
Trang 53Concept Connection Example 9-10 Valuing (Pricing) a Stock with CAPM
The required rate of return using the SML is:
kKelvin = 6 + (10 – 6)2.0 = 14%
Substituting this along with the 7% growth rate into the Gordon model yields the estimated price :
( ) ( )
0 0
Trang 54The Security Market Line (SML)
The Impact of Management Decisions on Stock Prices
Management decisions can influence a
stock's beta as well as future growth rates
An SML approach to valuation may be
relevant for policy decisions
Recall that management’s goal is generally to
maximize stock price
Trang 55Concept Connection Example 9-11 Strategic Decisions Based on
CAPM
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A new venture promises to increase Kelvin’s growth rate from 7% to 9% However, it will make the firm more risky, so its beta may increase from 2.0 to 2.3 T he current stock price is $22.90 If management’s objective is to maximize stock price, should Kelvin undertake the project ?
Solution: The new required rate of return will be:
kKelvin = 6 + (10 – 6)2.3 = 15.2%
Substituting this and 9% growth in the Gordon model yields:
Hence it seems the project will increase the stock’s price helping to achieve management’s goals 0 ( ) ( )
Trang 56The SML – Adjusting to Changes
A change in the risk-free rate
– Changes in the risk-free rate cause parallel shifts in the SML
A change in risk aversion
– Attitudes toward risk are reflected in the slope of the SML (kM – kRF)
Changes cause rotations of the SML around its vertical intercept at kRF
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Trang 57Figure 9-10 A Shift in the Security Market Line to Accommodate an Increase in the
Risk-Free Rate
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Trang 58Figure 9-11 A Rotation of the Security Market Line to Accommodate an Increase in Risk
Aversion
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Trang 59The Validity and Acceptance of the CAPM and its SML
CAPM is an abstraction of reality designed to help make predictions
CAPM is not universally accepted
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