Portfolio Selection and the Asset Allocation Decision

Chapter 8
Charles P. Jones, Investments: Analysis and Management,
Twelfth Edition, John Wiley & Sons
81



Diversification is key to optimal risk
management
Asset allocation is most important single
decision
Using Markowitz Principles
◦ Step 1: Identify optimal risk-return combinations
using the Markowitz efficient frontier analysis
 Estimate expected returns, variances and
covariances
◦ Step 2: Choose the final portfolio based on your
preferences for return relative to risk
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
Optimal diversification takes into account all
available information
Assumptions in portfolio theory
◦ A single investment period (one year)
◦ Liquid position (no transaction costs)
◦ Preferences based only on a portfolio’s expected
return and risk
83
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
Smallest portfolio risk for a given level of
expected return
Or largest expected return for a given level of
portfolio risk
From the set of all possible portfolios
◦ Only locate and analyze the subset known as the
efficient set
84

x
B

E(R) A
y
C
Risk = 

Efficient frontier or
Efficient set
(curved line from A
to B)
Global minimum
variance portfolio
(represented by
point A)
Portfolios on AB
dominate those on
AC
85
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

Portfolio weights are only variable that can
change in Markowitz analysis
Assume investors are risk averse
Indifference curves help select from efficient
set
◦ Description of preferences for risk and return
◦ Portfolio combinations which are equally desirable
◦ Match investor preferences with portfolio
possibilities
86
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
International diversification unlikely to offer
as much risk reduction as it has in the past
Markowitz portfolio selection model
◦ Assumes investors use only risk and return to
decide
◦ Generates a set of equally “good” portfolios
◦ Does not address the issues of borrowed money or
risk-free assets
◦ Cumbersome to apply
87

Another way to use Markowitz model is with
asset classes
◦ Allocation of portfolio assets to asset types
 Asset class rather than individual security decisions
likely most important for investors
◦ Can be used when investing internationally
◦ Different asset classes offers various returns and
levels of risk
 Correlation coefficients may be quite low
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
Includes two dimensions
◦ Diversifying between asset classes
◦ Diversifying within asset classes

Asset classes include
◦
◦
◦
◦
◦
◦
International equities
Bonds
Treasury Inflation-Indexed Securities (TIPS)
Real estate
Gold
Commodities
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Correlation among asset classes must be
considered
Correlations change over time
For individual investors, allocation depends
on
◦ Time horizon
◦ Risk tolerance

Diversified asset allocation doesn’t
necessarily provide benefits or guarantee
against loss
810

Index Mutual Funds and ETFs
◦ Investors can buy funds covering various asset
classes
 Domestic large-cap stocks, domestic small-cap
stocks
 International stocks
 Bond funds

Life Cycle Analysis

No one “correct” approach to allocation
◦ Varies asset allocation based on age of investor
◦ Life-cycle funds (target-date funds) hold various
asset classes and the allocation changes as investor
ages
811
Impact of Diversification on Risk

Total risk = systematic (nondiversifiable) risk
+ nonsystematic (diversifiable) risk
◦ Systematic risk is market risk and common to
virtually all securities
◦ Nonsystematic risk is company-specific risk


Total risk can go no lower than systematic
risk
Both risk components can vary over time
 Affects number of securities needed to diversify
812
p %
35
Total risk
Diversifiable (nonsystematic) risk
20
Nondiversifiable (systematic) risk
0
10
20
30
40
......
Number of securities in portfolio
100+
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