Presentation on theme: "Lecture Presentation Software to accompany Investment Analysis and Portfolio Management Seventh Edition by Frank K. Reilly & Keith C. Brown Chapter."— Presentation transcript:
1 Lecture Presentation Software to accompany Investment Analysis and Portfolio Management Seventh Edition by Frank K. Reilly & Keith C. BrownChapter 9
2 Chapter 9 – Multifactor Models of Risk and Return Questions to be answered:What is the arbitrage pricing theory (APT) and what are its similarities and differences relative to the CAPM?What are the major assumptions not required by the APT model compared to the CAPM?How do you test the APT by examining anomalies found with the CAPM?
3 Chapter 9 - Multifactor Models of Risk and Return What are the empirical test results related to the APT?Why do some authors contend that the APT model is untestable?What are the concerns related to the multiple factors of the APT model?
4 Chapter 9 - Multifactor Models of Risk and Return What are multifactor models and how are related to the APT?What are the steps necessary in developing a usable multifactor model?What are the multifactor models in practice?How is risk estimated in a multifactor setting?
5 Arbitrage Pricing Theory (APT) CAPM is criticized because of the difficulties in selecting a proxy for the market portfolio as a benchmarkAn alternative pricing theory with fewer assumptions was developed:Arbitrage Pricing Theory
6 Arbitrage Pricing Theory - APT Three major assumptions:1. Capital markets are perfectly competitive2. Investors always prefer more wealth to less wealth with certainty3. The stochastic process generating asset returns can be expressed as a linear function of a set of K factors or indexes15
7 Assumptions of CAPM That Were Not Required by APT APT does not assumeA market portfolio that contains all risky assets, and is mean-variance efficientNormally distributed security returnsQuadratic utility function
8 Arbitrage Pricing Theory (APT) For i = 1 to N where:= return on asset i during a specified time period= expected return for asset i= reaction in asset i’s returns to movements in a common factor k= a common factor with a zero mean that influences the returns on all assets= a unique effect on asset i’s return that, by assumption, is completely diversifiable in large portfolios and has a mean of zero= number of assetsRiEibikN
9 Arbitrage Pricing Theory (APT) Factors expected to have an impact on all assets:InflationGrowth in GNPMajor political upheavalsChanges in interest ratesAnd many more….Contrast with CAPM insistence that only beta is relevant
10 Arbitrage Pricing Theory (APT) determine how each asset reacts to this common factorEach asset may be affected by growth in GNP, but the effects will differIn application of the theory, the factors are not identifiedSimilar to the CAPM, the unique effects are independent and will be diversified away in a large portfolio
11 Arbitrage Pricing Theory (APT) APT assumes that, in equilibrium, the return on a zero-investment, zero-systematic-risk portfolio is zero when the unique effects are diversified awayThe expected return on any asset i (Ei) can be expressed as:
12 Arbitrage Pricing Theory (APT) where:= the expected return on an asset with zero systematic risk where= the risk premium related to each of the common factors - for example the risk premium related to interest rate riskbik = the pricing relationship between the risk premium and asset i - that is how responsive asset i is to this common factor k
13 Example of Two Stocks and a Two-Factor Model = changes in the rate of inflation. The risk premium related to this factor is 1 percent for every 1 percent change in the rate= percent growth in real GNP. The average risk premium related to this factor is 2 percent for every 1 percent change in the rate= the rate of return on a zero-systematic-risk asset (zero beta: bik=0) is 3 percent
14 Example of Two Stocks and a Two-Factor Model = the response of asset X to changes in the rate of inflation is 0.50= the response of asset Y to changes in the rate of inflation is 2.00= the response of asset X to changes in the growth rate of real GNP is 1.50= the response of asset Y to changes in the growth rate of real GNP is 1.75
15 Example of Two Stocks and a Two-Factor Model = (.01)bi (.02)bi2Ex = (.01)(0.50) + (.02)(1.50)= .065 = 6.5%Ey = (.01)(2.00) + (.02)(1.75)= .085 = 8.5%
16 Roll-Ross Study The methodology used in the study is as follows: Estimate the expected returns and the factor coefficients from time-series data on individual asset returnsUse these estimates to test the basic cross-sectional pricing conclusion implied by the APTThe authors concluded that the evidence generally supported the APT, but acknowledged that their tests were not conclusive
17 Extensions of the Roll-Ross Study Cho, Elton, and Gruber examined the number of factors in the return-generating process that were pricedDhrymes, Friend, and Gultekin (DFG) reexamined techniques and their limitations and found the number of factors varies with the size of the portfolio
18 The APT and Anomalies Small-firm effect January anomaly Reinganum - results inconsistent with the APTChen - supported the APT model over CAPMJanuary anomalyGultekin - APT not better than CAPMBurmeister and McElroy - effect not captured by model, but still rejected CAPM in favor of APT
19 Shanken’s Challenge to Testability of the APT If returns are not explained by a model, it is not considered rejection of a model; however if the factors do explain returns, it is considered supportAPT has no advantage because the factors need not be observable, so equivalent sets may conform to different factor structuresEmpirical formulation of the APT may yield different implications regarding the expected returns for a given set of securitiesThus, the theory cannot explain differential returns between securities because it cannot identify the relevant factor structure that explains the differential returns
20 Multifactor Models and Risk Estimation Multifactor Models in PracticeMacroeconomic-Based Risk Factor ModelsMicroeconomic-Based Risk Factor ModelsExtensions of Characteristic-Based Risk Factor Models
21 Estimating Risk in a Multifactor Setting: Examples Estimating Expected Returns for Individual StocksComparing Mutual Fund Risk Exposures