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Essentials of  Investments © 2001 Th e Mc Graw-H ill Com anies , Inc . Al l ri hts r eserved.   Fourth  Edition Irwin /  McGraw-Hill  Bodie • Kane • Marcus  1 Chapter  6 Risk and Return: Past and Prologue

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    Essentials ofInvestments

    2001 The McGraw-Hill Com anies, Inc. All ri hts reserved.

    FourthEdition

    Irwin / McGraw-Hill

    Bodie Kane Marcus1

    Chapter6

    Risk and Return: Pastand Prologue

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    FourthEdition

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    Rates of Return: Single Period

    HPR P P DP

    1 0 1

    0

    HPR = Holding Period Return

    P1= Ending price

    P0= Beginning price

    D1= Dividend during period one

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    Rates of Return: Single Period

    Example

    Ending Price = 24

    Beginning Price = 20Dividend = 1

    HPR = ( 24 - 20 + 1 )/ ( 20) = 25%

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    Data from Text Example p. 154

    1 2 3 4

    Assets(Beg.) 1.0 1.2 2.0 .8

    HPR .10 .25 (.20) .25TA (Before

    Net Flows 1.1 1.5 1.6 1.0

    Net Flows 0.1 0.5 (0.8) 0.0

    End Assets 1.2 2.0 .8 1.0

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    Returns Using Arithmetic and

    Geometric AveragingArithmetic

    ra = (r1+ r2+ r3+ ... rn) / n

    ra = (.10 + .25 - .20 + .25) / 4= .10 or 10%

    Geometric

    rg= {[(1+r1) (1+r2) .... (1+rn)]}1/n - 1

    rg= {[(1.1) (1.25) (.8) (1.25)]}1/4 - 1

    = (1.5150)1/4

    -1 = .0829 = 8.29%

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    Dollar Weighted Returns

    Internal Rate of Return (IRR) - thediscount rate that results present value

    of the future cash flows being equal tothe investment amount

    Considers changes in investment

    Initial Investment is an outflow

    Ending value is considered as an inflow

    Additional investment is a negative flow

    Reduced investment is a positive flow

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    Dollar Weighted Average Using TextExample

    Net CFs 1 2 3 4

    $ (mil) - .1 - .5 .8 1.0

    Solving for IRR

    1.0 = -.1/(1+r)1

    + -.5/(1+r)2

    + .8/(1+r)3

    +1.0/(1+r)4

    r = .0417 or 4.17%

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    Quoting Conventions

    APR = annual percentage rate

    (periods in year) X (rate for period)

    EAR = effective annual rate( 1+ rate for period)Periods per yr- 1

    Example: monthly return of 1%

    APR = 1% X 12 = 12%

    EAR = (1.01)12- 1 = 12.68%

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    Characteristics of ProbabilityDistributions

    1) Mean: most likely value

    2) Variance or standard deviation

    3) Skewness

    * If a distribution is approximately normal,the distribution is described bycharacteristics 1 and 2

    F h

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    r

    Symmetric distribution

    Normal Distribution

    s.d. s.d.

    F h

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    rNegative Positive

    Skewed Distribution: Large Negative

    Returns Possible

    Median

    F th

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    rNegative Positive

    Skewed Distribution: Large Positive

    Returns Possible

    Median

    F th13

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    Subjective returns

    p(s) = probability of a state

    r(s) = return if a state occurs

    1 to s states

    Measuring Mean: Scenario orSubjective Returns

    E(r) = p(s) r(s)Ss

    Fourth14

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    Numerical Example: Subjective or

    Scenario DistributionsState Prob. of State rinState

    1 .1 -.05

    2 .2 .053 .4 .15

    4 .2 .25

    5 .1 .35

    E(r) = (.1)(-.05) + (.2)(.05)...+ (.1)(.35)

    E(r) = .15

    i l fFourthdi15

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    Standard deviation = [variance]1/2

    Measuring Variance or Dispersion of

    ReturnsSubjective or Scenario

    Variance = Ss

    p(s) [rs - E(r)]2

    Var =[(.1)(-.05-.15)2+(.2)(.05- .15)2...+ .1(.35-.15)2]Var= .01199

    S.D.= [ .01199] 1/2 = .1095

    Using Our Example:

    E i l f IFourthB di K M16

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    Real vs. Nominal Rates

    Fisher effect: Approximation

    nominal rate = real rate + inflation premium

    R = r + i or r = R - i

    Example r = 3%, i = 6%

    R = 9% = 3% + 6% or 3% = 9% - 6%

    Fisher effect: Exact

    r = (R - i) / (1 + i)2.83% = (9%-6%) / (1.06)

    E i l f IFourthB di K M17

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    Annual Holding Period ReturnsFrom Figure 6.1 of Text

    Geom Arith Stan.

    Series Mean% Mean% Dev.%

    Lg Stk 11.01 13.00 20.33Sm Stk 12.46 18.77 39.95

    LT Gov 5.26 5.54 7.99

    T-Bills 3.75 3.80 3.31

    Inflation 3.08 3.18 4.49

    E ti l f I t tFourthB di K M18

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    Annual Holding Period Risk

    Premiums and Real ReturnsRisk RealSeries Premiums% Returns%

    Lg Stk 9.2 9.82Sm Stk 14.97 15.59

    LT Gov 1.74 2.36

    T-Bills --- 0.62

    Inflation --- ---

    E ti l f I t tFourthB di K M19

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    Possible to split investment fundsbetween safe and risky assets

    Risk free asset: proxy; T-bills Risky asset: stock (or a portfolio)

    Allocating Capital Between Risky &Risk-Free Assets

    E ti l f I t tFourthBodie Kane Marc s20

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    Allocating Capital Between Risky &

    Risk-Free Assets (cont.) Issues Examine risk/ return tradeoff

    Demonstrate how different degrees of riskaversion will affect allocations betweenrisky and risk free assets

    E ti l f I t tFourthBodie Kane Marcus21

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    rf= 7% srf = 0%E(rp) = 15% sp= 22%

    y = % in p (1-y) = % in rf

    Example Using the Numbers in

    Chapter 6 (pp 171-173)

    Essentials of InvestmentsFourthBodie Kane Marcus22

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    E(rc) = yE(rp) + (1 - y)rf

    rc= complete or combined portfolio

    For example, y = .75

    E(rc) = .75(.15) + .25(.07)= .13 or 13%

    Expected Returns for Combinations

    Essentials of InvestmentsFourthBodie Kane Marcus23

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    E(r)

    E(rp) = 15%

    rf= 7%

    22%0

    P

    F

    Possible Combinations

    s

    Essentials of InvestmentsFourthBodie Kane Marcus24

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    pc =

    Sincerf

    y

    Variance on the Possible CombinedPortfolios

    = 0, then

    s

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    c = .75(.22) = .165 or 16.5%

    If y = .75, then

    c = 1(.22) = .22 or 22%

    If y = 1

    c = 0(.22) = .00 or 0%

    If y = 0

    Combinations Without Leverage

    sss

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    Using Leverage with CapitalAllocation Line

    Borrow at the Risk-Free Rate and investin stock

    Using 50% Leveragerc= (-.5) (.07) + (1.5) (.15) = .19

    sc= (1.5) (.22) = .33

    Essentials of InvestmentsFourthEdi iBodie Kane Marcus27

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    E(r)

    E(rp) = 15%

    rf= 7%

    = 22%0

    P

    F

    P

    ) S = 8/22

    E(rp) - rf= 8%

    CAL

    (Capital

    AllocationLine)

    s

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    Risk Aversion and Allocation

    Greater levels of risk aversion lead tolarger proportions of the risk free rate

    Lower levels of risk aversion lead tolarger proportions of the portfolio ofrisky assets

    Willingness to accept high levels of riskfor high levels of returns would result inleveraged combinations

    Essentials of Investments FourthEditiBodie Kane Marcus29

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    Quantifying Risk Aversion

    pfp ArrE s 005.E(rp) = Expected return on portfolio p

    rf = the risk free rate

    .005 = Scale factor

    A x sp= Proportional risk premium

    The larger A is, the larger will be the

    addedreturn required for risk

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    Quantifying Risk Aversion

    rrEA

    p

    fp

    2

    .005

    )(

    Rearranging the equation and solving for A

    Many studies have concluded that

    investors average risk aversion isbetween 2 and 4

    Essentials of Investments FourthEditionBodie Kane Marcus31

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    Chapter7

    EfficientDiversification

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    rp = W1r1 +W2r2W1= Proportion of funds in Security 1

    W2= Proportion of funds in Security 2r1 = Expected return on Security 1

    r2 = Expected return on Security 2

    Two-Security Portfolio: Return

    WiSi=1

    n

    = 1

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    sp2= w12s12+ w22s22+ 2W1W2 Cov(r1r2)s12 = Variance of Security 1s22 = Variance of Security 2

    Cov(r1r2) = Covariance of returns for

    Security 1 and Security 2

    Two-Security Portfolio: Risk

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    Covariance

    r1,2

    = Correlation coefficient of

    returns

    Cov(r1r2) = r1 2s1s2

    s1= Standard deviation ofreturns for Security 1s2= Standard deviation ofreturns for Security 2

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    Correlation Coefficients: Possible

    Values

    If r = 1.0, the securities would beperfectly positively correlated

    If r = - 1.0, the securities would beperfectly negatively correlated

    Range of values for r1,2

    -1.0 < r < 1.0

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    s2p = W12s12+ W22s22+ 2W1W2

    rp = W1r1 +W2r2 + W3r3

    Cov(r1r2)

    + W32s32

    Cov(r1r3)+ 2W1W3

    Cov(r2r3)+ 2W2W3

    Three-Security Portfolio

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    rp= Weighted average of the

    n securities

    sp2 = (Consider all pair-wisecovariance measures)

    In General, For an n-SecurityPortfolio:

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    E(rp) = W1r1 +W2r2

    Two-Security Portfolio

    sp2= w12s12+ w22s22+ 2W1W2 Cov(r1r2)sp= [w12s12+ w22s22+ 2W1W2Cov(r1r2)]1/2

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    r= 0

    E(r)

    r= 1r= -1

    r= -1r= .3

    13%

    8%

    12% 20% St. Dev

    TWO-SECURITY PORTFOLIOS WITH

    DIFFERENT CORRELATIONS

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    Portfolio Risk/Return Two Securities:Correlation Effects

    Relationship depends on correlationcoefficient

    -1.0 < r< +1.0 The smaller the correlation, the greater

    the risk reduction potential

    Ifr = +1.0, no risk reduction is possible

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    1

    1 2

    - Cov(r1r2)

    W1

    =

    + - 2Cov(r1r2)

    2

    W2 = (1 - W1)

    Minimum Variance Combination

    s 2s 2

    2E(r2) = .14 = .20Sec 212 = .2

    E(r1) = .10 = .15Sec 1 ss r

    s 2

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    W1 =(.2)2- (.2)(.15)(.2)

    (.15)2

    + (.2)2

    - 2(.2)(.15)(.2)

    W1 = .6733

    W2 = (1 - .6733) = .3267

    Minimum VarianceCombination: r= .2

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    rp= .6733(.10) + .3267(.14) = .1131

    p = [(.6733)2(.15)2 + (.3267)2(.2)2 +

    2(.6733)(.3267)(.2)(.15)(.2)]1/2

    p= [.0171]1/2

    = .1308

    Minimum Variance: Return and Riskwith r= .2

    s

    s

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    W1 =(.2)2- (.2)(.15)(.2)

    (.15)2

    + (.2)2

    - 2(.2)(.15)(-.3)

    W1 = .6087

    W2 = (1 - .6087) = .3913

    Minimum VarianceCombination: r= -.3

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    rp= .6087(.10) + .3913(.14) = .1157

    p = [(.6087)2(.15)2 + (.3913)2(.2)2 +

    2(.6087)(.3913)(.2)(.15)(-.3)]1/2

    p= [.0102]

    1/2= .1009

    Minimum Variance: Return and Risk

    with r= -.3

    s

    s

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    Extending Concepts to All Securities

    The optimal combinations result inlowest level of risk for a given return

    The optimal trade-off is described as theefficient frontier

    These portfolios are dominant

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    E(r)The minimum-variance frontier of

    risky assets

    Efficientfrontier

    Globalminimum

    variance

    portfolio Minimum

    variancefrontier

    Individual

    assets

    St. Dev.

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    Extending to Include Riskless Asset

    The optimal combination becomeslinear

    A single combination of risky andriskless assets will dominate

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    E(r)

    CAL (Global

    minimum variance)

    CAL (A)CAL (P)

    M

    P

    A

    F

    P P&F A&FM

    A

    G

    P

    M

    s

    ALTERNATIVE CALS

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    Dominant CAL with a Risk-FreeInvestment (F)

    CAL(P) dominates other lines -- it has thebest risk/return or the largest slope

    Slope = (E(R) - Rf) / s[ E(RP) - Rf) / s P] > [E(RA) - Rf) / sA]

    Regardless of risk preferences

    combinations of P & F dominate

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    Single Factor Model

    ri= E(Ri) + iF + e

    i= index of a securities particular returnto the factor

    F= some macro factor; in this case F isunanticipated movement; F is commonlyrelated to security returns

    Assumption: a broad market index like theS&P500 is the common factor

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    Single Index Model

    Risk PremMarket Risk Prem

    or Index Risk Prem

    i = the stocks expected return if the

    markets excess return is zero

    i(rm- rf) = the component of return due tomovements in the market index

    (rm- rf) = 0

    ei = firm specific component, not due to market

    movements

    a

    errrr ifmiifi a

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    Let: Ri = (ri- rf)

    Rm = (rm- rf)

    Risk premium

    format

    Ri = ai+ i(Rm) + ei

    Risk Premium Format

    Essentials ofInvestments FourthEditionBodie Kane Marcus54

    E ti ti th I d M d l

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    Estimating the Index ModelExcess Returns (i)

    Security

    Characteristic

    Line

    . ..

    ..

    .

    . .

    . ..

    . .

    .

    . .

    . ..

    ..

    .

    . .

    . ..

    .

    ..

    ..

    ..

    .

    . ..

    . .

    .

    . ... .. .

    . .

    Excess returns

    on market index

    Ri= ai+ iRm+ ei

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    Components of Risk

    Market or systematic risk: risk related to themacro economic factor or market index

    Unsystematic or firm specific risk: risk not

    related to the macro factor or market index Total risk = Systematic + Unsystematic

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    Measuring Components of Risk

    si2 = i

    2sm2 + s2(ei)

    where;

    si2 = total variance

    i2sm

    2 = systematic variance

    s2(ei) = unsystematic variance

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    Total Risk = Systematic Risk +Unsystematic Risk

    Systematic Risk/Total Risk = r2

    i2 sm

    2 / s2= r2

    i2sm

    2/ i2sm

    2 + s2(ei) = r2

    Examining Percentage of Variance

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    Advantages of the Single Index Model

    Reduces the number of inputs fordiversification

    Easier for security analysts to specialize

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    Chapter8

    Capital Asset Pricing

    and Arbitrage

    Pricing Theory

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    Capital Asset Pricing Model (CAPM)

    Equilibrium model that underlies all modernfinancial theory

    Derived using principles of diversificationwith simplified assumptions

    Markowitz, Sharpe, Lintner and Mossin areresearchers credited with its development

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    Assumptions

    Individual investors are price takers

    Single-period investment horizon

    Investments are limited to tradedfinancial assets

    No taxes, and transaction costs

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    Assumptions (cont.)

    Information is costless and available toall investors

    Investors are rational mean-varianceoptimizers

    Homogeneous expectations

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    Resulting Equilibrium Conditions

    All investors will hold the same portfoliofor risky assetsmarket portfolio

    Market portfolio contains all securitiesand the proportion of each security is itsmarket value as a percentage of totalmarket value

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    Risk premium on the market dependson the average risk aversion of all

    market participants Risk premium on an individual security

    is a function of its covariance with the

    market

    Resulting Equilibrium Conditions

    (cont.)

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    E(r)

    E(rM)

    rf

    M CML

    sm

    Capital Market Line

    s

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    M = Market portfoliorf = Risk free rate

    E(rM) - rf = Market risk premium

    E(rM) - rf = Market price of risk

    = Slope of the CAPM

    Slope and Market Risk Premium

    Ms

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    Expected Return and Risk onIndividual Securities

    The risk premium on individualsecurities is a function of the individual

    securitys contribution to the risk of themarket portfolio

    Individual securitys risk premium is a

    function of the covariance of returnswith the assets that make up the marketportfolio

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    E(r)

    E(rM)

    rf

    SML

    M

    = 1.0

    Security Market Line

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    SML Relationships

    = [COV(ri,rm)] / sm2

    Slope SML = E(rm) - rf

    = market risk premium

    SML = rf + [E(rm) - rf]

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    Sample Calculations for SML

    E(rm) - rf= .08 rf = .03

    x = 1.25E(rx) = .03 + 1.25(.08) = .13 or 13%

    y= .6e(ry) = .03 + .6(.08) = .078 or 7.8%

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    E(r)

    Rx=13%

    SML

    m

    1.0

    Rm=11%

    Ry=7.8%

    3%

    x

    1.25

    y.6

    .08

    Graph of Sample Calculations

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    E(r)

    15%

    SML

    1.0

    Rm=11%

    rf=3%

    1.25

    Disequilibrium Example

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    Disequilibrium Example

    Suppose a security with a of 1.25 isoffering expected return of 15%

    According to SML, it should be 13%

    Underpriced: offering too high of a rateof return for its level of risk

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    Security Characteristic Line

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    Security Characteristic LineExcess Returns (i)

    SCL

    ..

    ...

    .

    . .

    . ..

    . .

    .

    . .

    . ..

    . .

    .

    . .

    . ..

    .

    ..

    ..

    .

    .

    .

    . ..

    . .

    .

    . ... .. .

    . .

    Excess returns

    on market index

    Ri= ai+ iRm+ ei

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    Using the Text Example p. 245, Table

    8.5:

    Jan.Feb...

    DecMeanStd Dev

    5.41-3.44..

    2.43-.604.97

    7.24.93..

    3.901.753.32

    Excess

    Mkt. Ret.

    Excess

    GM Ret.

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    Estimated coefficientStd error of estimate

    Variance of residuals = 12.601

    Std dev of residuals = 3.550R-SQR = 0.575

    -2.590(1.547)

    1.1357(0.309)

    rGM- rf = + (rm- rf)

    Regression Results:

    aa

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    Arbitrage Pricing Theory

    Arbitrage - arises if an investor canconstruct a zero investment portfoliowith a sure profit

    Since no investment is required, aninvestor can create large positions tosecure large levels of profit

    In efficient markets, profitable arbitrageopportunities will quickly disappear

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    Arbitrage Example from Text pp. 255-

    257 Current Expected StandardStock Price$ Return% Dev.%

    A 10 25.0 29.58

    B 10 20.0 33.91

    C 10 32.5 48.15

    D 10 22.5 8.58

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    Arbitrage Portfolio

    Mean Stan. Correlation

    Return Dev. Of Returns

    Portfolio

    A,B,C 25.83 6.40 0.94

    D 22.25 8.58

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    Arbitrage Action and Returns

    E. Ret.

    St.Dev.

    * P* D

    Short 3 shares of D and buy 1 of A, B & C to form

    P

    You earn a higher rate on the investment than

    you pay on the short sale

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    APT and CAPM Compared

    APT applies to well diversified portfolios andnot necessarily to individual stocks

    With APT it is possible for some individual

    stocks to be mispriced - not lie on the SML APT is more general in that it gets to an

    expected return and beta relationship withoutthe assumption of the market portfolio

    APT can be extended to multifactor models