Risk and Return in Financial Markets

undefined
 
12
 
R
e
t
u
r
n
,
 
R
i
s
k
,
 
a
n
d
 
t
h
e
S
e
c
u
r
i
t
y
 
M
a
r
k
e
t
 
L
i
n
e
 
Learning Objectives
 
 
Our goal in this chapter is to define risk more precisely,
and discuss how to measure it.
 
In addition, we will quantify the relation between risk and
return in financial markets.
 
More specifically, our goal is to understand
 
 
 
1. The difference between expected and unexpected returns.
 
2. The difference between systematic risk and unsystematic risk.
 
3. The security market line and the capital asset pricing model.
 
4. The importance of beta.
 
2
 
Expected and Unexpected Returns
 
 
The return on any stock traded in a financial market is composed of
two parts.
T
h
e
 
n
o
r
m
a
l
,
 
o
r
 
e
x
p
e
c
t
e
d
,
 
p
a
r
t
 
o
f
 
t
h
e
 
r
e
t
u
r
n
 
i
s
 
t
h
e
 
r
e
t
u
r
n
 
t
h
a
t
i
n
v
e
s
t
o
r
s
 
p
r
e
d
i
c
t
 
o
r
 
e
x
p
e
c
t
.
T
h
e
 
u
n
c
e
r
t
a
i
n
,
 
o
r
 
r
i
s
k
y
,
 
p
a
r
t
 
o
f
 
t
h
e
 
r
e
t
u
r
n
 
c
o
m
e
s
 
f
r
o
m
 
u
n
e
x
p
e
c
t
e
d
i
n
f
o
r
m
a
t
i
o
n
 
r
e
v
e
a
l
e
d
 
d
u
r
i
n
g
 
t
h
e
 
y
e
a
r
.
 
 
 
 
3
 
Announcements and News
 
Firms make periodic announcements about events that may
significantly impact the profits of the firm.
E
a
r
n
i
n
g
s
P
r
o
d
u
c
t
 
d
e
v
e
l
o
p
m
e
n
t
P
e
r
s
o
n
n
e
l
The impact of an announcement depends on how much of the
announcement represents new information.
W
h
e
n
 
t
h
e
 
s
i
t
u
a
t
i
o
n
 
i
s
 
n
o
t
 
a
s
 
b
a
d
 
a
s
 
p
r
e
v
i
o
u
s
l
y
 
t
h
o
u
g
h
t
,
 
w
h
a
t
 
s
e
e
m
s
t
o
 
b
e
 
b
a
d
 
n
e
w
s
 
i
s
 
a
c
t
u
a
l
l
y
 
g
o
o
d
 
n
e
w
s
.
W
h
e
n
 
t
h
e
 
s
i
t
u
a
t
i
o
n
 
i
s
 
n
o
t
 
a
s
 
g
o
o
d
 
a
s
 
p
r
e
v
i
o
u
s
l
y
 
t
h
o
u
g
h
t
,
 
w
h
a
t
s
e
e
m
s
 
t
o
 
b
e
 
g
o
o
d
 
n
e
w
s
 
i
s
 
a
c
t
u
a
l
l
y
 
b
a
d
 
n
e
w
s
.
News about the future is what really matters.
M
a
r
k
e
t
 
p
a
r
t
i
c
i
p
a
n
t
s
 
f
a
c
t
o
r
 
p
r
e
d
i
c
t
i
o
n
s
 
a
b
o
u
t
 
t
h
e
 
f
u
t
u
r
e
 
i
n
t
o
 
t
h
e
e
x
p
e
c
t
e
d
 
p
a
r
t
 
o
f
 
t
h
e
 
s
t
o
c
k
 
r
e
t
u
r
n
.
A
n
n
o
u
n
c
e
m
e
n
t
 
=
 
E
x
p
e
c
t
e
d
 
N
e
w
s
 
+
 
S
u
r
p
r
i
s
e
 
N
e
w
s
 
4
 
Systematic and Unsystematic Risk
 
 
S
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
r
i
s
k
 
t
h
a
t
 
i
n
f
l
u
e
n
c
e
s
 
a
 
l
a
r
g
e
 
n
u
m
b
e
r
 
o
f
a
s
s
e
t
s
.
 
 
A
l
s
o
 
c
a
l
l
e
d
 
m
a
r
k
e
t
 
r
i
s
k
.
 
U
n
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
r
i
s
k
 
t
h
a
t
 
i
n
f
l
u
e
n
c
e
s
 
a
 
s
i
n
g
l
e
c
o
m
p
a
n
y
 
o
r
 
a
 
s
m
a
l
l
 
g
r
o
u
p
 
o
f
 
c
o
m
p
a
n
i
e
s
.
 
A
l
s
o
 
c
a
l
l
e
d
u
n
i
q
u
e
 
r
i
s
k
 
o
r
 
f
i
r
m
-
s
p
e
c
i
f
i
c
 
r
i
s
k
.
 
 
T
o
t
a
l
 
r
i
s
k
 
=
 
S
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
+
 
U
n
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
5
Pop Quiz:
Systematic Risk or Unsystematic Risk?
 
The government announces that inflation unexpectedly
jumped by 2 percent last month.
  
Systematic Risk
One of Big Widget’s major suppliers goes bankruptcy.
  
Unsystematic Risk
The head of accounting department of Big Widget
announces that the company’s current ratio has been
severely deteriorating.
  
Unsystematic Risk
Congress approves changes to the tax code that will
increase the top marginal corporate tax rate.
  
Systematic Risk
6
 
Systematic and Unsystematic
Components of Return
 
 
Recall:
 
  R – E(R)
 
= U
 
  
= Systematic portion
+ Unsystematic portion
 
= m + 
 
 
   R – E(R) = m + 
 
7
 
Diversification and Risk
 
 
In a large portfolio:
Some stocks will go up in value because of positive company-
specific events, while
Others will go down in value because of negative company-
specific events.
Unsystematic risk is essentially eliminated by
diversification, so a portfolio with many assets has almost
no unsystematic risk.
U
n
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
a
l
s
o
 
c
a
l
l
e
d
 
d
i
v
e
r
s
i
f
i
a
b
l
e
 
r
i
s
k
.
S
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
a
l
s
o
 
c
a
l
l
e
d
 
n
o
n
-
d
i
v
e
r
s
i
f
i
a
b
l
e
 
r
i
s
k
.
 
8
 
The Systematic Risk Principle
 
 
What determines the size of the risk premium on a risky
asset?
 
T
h
e
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
p
r
i
n
c
i
p
l
e
 
s
t
a
t
e
s
:
 
 
 
 
 
T
h
e
 
e
x
p
e
c
t
e
d
 
r
e
t
u
r
n
 
o
n
 
a
n
 
a
s
s
e
t
 
d
e
p
e
n
d
s
o
n
l
y
 
o
n
 
i
t
s
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
.
S
o
,
 
n
o
 
m
a
t
t
e
r
 
h
o
w
 
m
u
c
h
 
t
o
t
a
l
 
r
i
s
k
 
a
n
 
a
s
s
e
t
 
h
a
s
,
 
o
n
l
y
 
t
h
e
s
y
s
t
e
m
a
t
i
c
 
p
o
r
t
i
o
n
 
i
s
 
r
e
l
e
v
a
n
t
 
i
n
 
d
e
t
e
r
m
i
n
i
n
g
 
t
h
e
e
x
p
e
c
t
e
d
 
r
e
t
u
r
n
 
(
a
n
d
 
t
h
e
 
r
i
s
k
 
p
r
e
m
i
u
m
)
 
o
n
 
t
h
a
t
 
a
s
s
e
t
.
 
 
9
 
Measuring Systematic Risk
 
 
To be compensated for risk, the risk has to be special.
U
n
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
n
o
t
 
s
p
e
c
i
a
l
.
S
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
i
s
 
s
p
e
c
i
a
l
.
 
T
h
e
 
B
e
t
a
 
c
o
e
f
f
i
c
i
e
n
t
 
(
)
 
m
e
a
s
u
r
e
s
 
t
h
e
 
r
e
l
a
t
i
v
e
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
o
f
 
a
n
a
s
s
e
t
.
A
s
s
e
t
s
 
w
i
t
h
 
B
e
t
a
s
 
l
a
r
g
e
r
 
t
h
a
n
 
1
.
0
 
h
a
v
e
 
m
o
r
e
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
t
h
a
n
a
v
e
r
a
g
e
.
A
s
s
e
t
s
 
w
i
t
h
 
B
e
t
a
s
 
s
m
a
l
l
e
r
 
t
h
a
n
 
1
.
0
 
h
a
v
e
 
l
e
s
s
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
t
h
a
n
a
v
e
r
a
g
e
.
 
Because assets with larger betas have greater systematic risks, they
will have greater expected returns.
N
o
t
e
 
t
h
a
t
 
n
o
t
 
a
l
l
 
B
e
t
a
s
 
a
r
e
 
c
r
e
a
t
e
d
 
e
q
u
a
l
l
y
.
 
10
 
Betas with Respect
to the S&P 500 for
Individual Stocks
(based on monthly
data for 2004–2008)
 
11
 
Finding a Beta on the Web
 
12
 
Portfolio Betas
 
 
The total risk of a portfolio has no simple relation to the
total risk of the assets in the portfolio.
Recall the variance of a portfolio equation
For two assets, you need two variances and the covariance.
For four assets, you need four variances, and six covariances.
 
In contrast, a portfolio Beta can be calculated just like the
expected return of a portfolio.
That is, you can multiply each asset’s Beta by its portfolio weight
and then add the results to get the portfolio’s Beta.
 
13
 
Example: Calculating a Portfolio Beta
 
 
Using Value Line data from Table 12.1, we see
Beta for Southwest Airlines (LUV) is 1.05
Beta for General Motors (GM) 1.45
 
You put half your money into LUV and half into GM.
 
What is your portfolio Beta?
 
 
12-14
 
Capital Asset Pricing Model (CAPM)
 
 
Now, we will go back to the Markowitz's efficient market
frontier.
 
In order to derive the CAPM, Capital Market Line (CML),
Security Market Line (SML).
 
Here, we will try to derive the security market line (SML),
which is a linear line characterized with risk-free rate and
the market portfolio.
 
A series of graphs explain all….
 
15
 
Efficient Frontier with Ten Stocks Versus
Three Stocks
 
 
16
 
Risk-Free Saving and Borrowing
 
 
Risk can also be reduced by investing a portion of a
portfolio in a risk-free investment, like T-Bills. However,
doing so will likely reduce the expected return.
On the other hand, an aggressive investor who is seeking
high expected returns might decide to borrow money to
invest even more in the stock market.
 
17
 
Investing in Risk-Free Securities
 
 
Consider an arbitrary risky portfolio and the effect on risk
and return of putting a fraction of the money in the
portfolio, while leaving the remaining fraction in risk-free
Treasury bills.
The expected return would be:
 
18
 
Investing in Risk-Free Securities (cont'd)
 
 
The standard deviation of the portfolio would be
calculated as:
 
 
 
 
 
 
 
Note: The standard deviation is only a fraction of the
volatility of the risky portfolio, based on the amount
invested in the risky portfolio.
 
19
 
The Risk–Return Combinations  from Combining a Risk-
Free Investment and a Risky Portfolio
 
 
20
 
The Tangent or Efficient Portfolio
 
 
21
 
The Capital Market Line (CML)
 
22
 
The Market Portfolio
 
 
Because portfolio M lies at the point of tangency, it has
the highest portfolio possibility line
So, everybody will want to invest in Portfolio M and borrow or
lend to be somewhere on the straight line.
This line is called the Capital Market Line (CML).
 
Therefore this portfolio must include ALL RISKY ASSETS
not only U.S. common stocks but also all risky assets, such as
Non-U.S. stocks, options, real estate, coins, and art.
 
23
 
Continued
 
 
Because the market is in equilibrium, all assets are included in
this portfolio in proportion to their market value
 
Because it contains all risky assets, it is a completely
diversified portfolio, which means that all the unique risk of
individual assets (unsystematic risk) is diversified away
 
All portfolios on the CML are perfectly positively correlated
with each other and with the completely diversified market
Portfolio M
 
A completely diversified portfolio would have a correlation with
the market portfolio of +1.00
 
24
 
The CML and the Separation Theorem
 
Investors preferring more risk might borrow funds at the RFR and
invest everything in the market portfolio
 
The decision of both investors is to invest in portfolio M along the
CML (the investment decision)
 
M
 
CML
 
RFR
 
B
 
A
 
25
 
The Security Market Line
 
 
T
h
e
r
e
 
i
s
 
a
 
l
i
n
e
a
r
 
r
e
l
a
t
i
o
n
s
h
i
p
 
b
e
t
w
e
e
n
 
a
 
s
t
o
c
k
s
 
b
e
t
a
 
a
n
d
i
t
s
 
e
x
p
e
c
t
e
d
 
r
e
t
u
r
n
 
(
S
e
e
 
f
i
g
u
r
e
 
o
n
 
n
e
x
t
 
s
l
i
d
e
)
.
 
T
h
e
s
e
c
u
r
i
t
y
 
m
a
r
k
e
t
 
l
i
n
e
 
(
S
M
L
)
 
i
s
 
g
r
a
p
h
e
d
 
a
s
 
t
h
e
 
l
i
n
e
t
h
r
o
u
g
h
 
t
h
e
 
r
i
s
k
-
f
r
e
e
 
i
n
v
e
s
t
m
e
n
t
 
a
n
d
 
t
h
e
 
m
a
r
k
e
t
.
 
According to the CAPM, if the expected return and
beta for individual securities are plotted, they should
all fall along the SML.
 
26
 
The Capital Market Line  and the Security
Market Line
 
27
 
The Capital Market Line and the Security
Market Line
 
The CML depicts portfolios combining the risk-free investment and the efficient portfolio,
and shows the highest expected return that we can attain for each level of volatility.
According to the CAPM, the market portfolio is on the CML and all other stocks and
portfolios contain diversifiable risk and lie to the right of the CML, as illustrated for
Exxon Mobil (XOM).
 
28
 
The Capital Market Line  and the Security
Market Line
 
 The SML shows the expected return for each security as a function of its beta
with the market. According to the CAPM, the market portfolio is efficient, so all
stocks and portfolios should lie on the SML.
 
29
 
Beta and the Risk Premium, I.
 
 
Consider a portfolio made up of asset A and a risk-free asset.
For asset A, 
E(R
A
)
 = 16% and 
A
 = 1.6
The risk-free rate 
R
f
 = 4%. Note that for a risk-free asset, 
 = 0 by
definition.
 
We can calculate some different possible portfolio expected returns
and betas by changing the percentages invested in these two assets.
 
Note that if the investor borrows at the risk-free rate and invests the
proceeds in asset A, the investment in asset A will exceed 100%.
 
30
 
Beta and the Risk Premium, II.
 
31
 
Portfolio Expected Returns
and Betas for Asset A
 
32
 
The Reward-to-Risk Ratio
 
 
Notice that all the combinations of portfolio expected
returns and betas fall on a straight line.
Slope (Rise over Run):
 
 
W
h
a
t
 
t
h
i
s
 
t
e
l
l
s
 
u
s
 
i
s
 
t
h
a
t
 
a
s
s
e
t
 
A
 
o
f
f
e
r
s
 
a
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
r
a
t
i
o
 
o
f
 
7
.
5
0
%
.
 
I
n
 
o
t
h
e
r
 
w
o
r
d
s
,
 
a
s
s
e
t
 
A
 
h
a
s
 
a
 
r
i
s
k
p
r
e
m
i
u
m
 
o
f
 
7
.
5
0
%
 
p
e
r
 
u
n
i
t
 
o
f
 
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
.
 
33
 
Performance Evaluation Measures
 
T
h
e
 
S
h
a
r
p
e
 
R
a
t
i
o
 
T
h
e
 
S
h
a
r
p
e
 
r
a
t
i
o
 
i
s
 
a
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
 
r
a
t
i
o
 
t
h
a
t
 
f
o
c
u
s
e
s
o
n
 
t
o
t
a
l
 
r
i
s
k
.
 
It is computed as a portfolio’s risk premium divided by
the standard deviation of the portfolio’s return.
 
 
34
 
Performance Evaluation Measures
 
T
h
e
 
T
r
e
y
n
o
r
 
R
a
t
i
o
T
h
e
 
T
r
e
y
n
o
r
 
r
a
t
i
o
 
i
s
 
a
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
 
r
a
t
i
o
 
t
h
a
t
 
l
o
o
k
s
 
a
t
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
o
n
l
y
.
It is computed as a portfolio’s risk premium divided by
the portfolio’s beta coefficient.
 
35
 
The Basic Argument, I.
 
 
Recall that for asset A: 
E(R
A
)
 = 16% and 
A
 = 1.6
 
Suppose there is a second asset, asset B.
For asset B: 
 
E(R
B
)
 = 12% and 
A
 = 1.2
 
Which investment is better, asset A or asset B?
Asset A has a higher expected return
Asset B has a lower systematic risk measure
 
36
 
The Basic Argument, II
 
 
As before with Asset A, we can calculate some different possible
portfolio expected returns and betas by changing the percentages
invested in asset B and the risk-free rate.
 
 
 
12-37
 
Portfolio Expected Returns
and Betas for Asset B
 
38
 
Portfolio Expected Returns
and Betas for Both Assets
 
39
 
The Fundamental Result, I.
 
 
The situation we have described for assets A and B cannot persist in
a well-organized, active market
Investors will be attracted to asset A (and buy A shares)
Investors will shy away from asset B (and sell B shares)
This buying and selling will make
The price of A shares increase
The price of B shares decrease
This price adjustment continues until the two assets plot on exactly
the same line.
 
That is, until:
 
40
 
The Fundamental Result, II.
 
 
I
n
 
g
e
n
e
r
a
l
 
T
h
e
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
 
r
a
t
i
o
 
m
u
s
t
 
b
e
 
t
h
e
 
s
a
m
e
 
f
o
r
 
a
l
l
 
a
s
s
e
t
s
i
n
 
a
 
c
o
m
p
e
t
i
t
i
v
e
 
f
i
n
a
n
c
i
a
l
 
m
a
r
k
e
t
.
If one asset has twice as much systematic risk as another
asset, its risk premium will simply be twice as large.
B
e
c
a
u
s
e
 
t
h
e
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
 
r
a
t
i
o
 
m
u
s
t
 
b
e
 
t
h
e
 
s
a
m
e
,
 
a
l
l
a
s
s
e
t
s
 
i
n
 
t
h
e
 
m
a
r
k
e
t
 
m
u
s
t
 
p
l
o
t
 
o
n
 
t
h
e
 
s
a
m
e
 
l
i
n
e
.
 
41
 
The Fundamental Result, III.
 
42
 
The Security Market Line (SML)
 
 
T
h
e
 
S
e
c
u
r
i
t
y
 
m
a
r
k
e
t
 
l
i
n
e
 
(
S
M
L
)
 
i
s
 
a
 
g
r
a
p
h
i
c
a
l
r
e
p
r
e
s
e
n
t
a
t
i
o
n
 
o
f
 
t
h
e
 
l
i
n
e
a
r
 
r
e
l
a
t
i
o
n
s
h
i
p
 
b
e
t
w
e
e
n
s
y
s
t
e
m
a
t
i
c
 
r
i
s
k
 
a
n
d
 
e
x
p
e
c
t
e
d
 
r
e
t
u
r
n
 
i
n
 
f
i
n
a
n
c
i
a
l
 
m
a
r
k
e
t
s
.
 
For a market portfolio,
 
 
43
 
The Security Market Line, II.
 
 
T
h
e
 
t
e
r
m
 
 
E
(
R
M
)
 
 
R
f
 
 
i
s
 
o
f
t
e
n
 
c
a
l
l
e
d
 
t
h
e
 
m
a
r
k
e
t
 
r
i
s
k
p
r
e
m
i
u
m
 
b
e
c
a
u
s
e
 
i
t
 
i
s
 
t
h
e
 
r
i
s
k
 
p
r
e
m
i
u
m
 
o
n
 
a
 
m
a
r
k
e
t
p
o
r
t
f
o
l
i
o
.
 
For any asset 
i
 in the market:
 
 
 
 
 
 
 
 
S
e
t
t
i
n
g
 
t
h
e
 
r
e
w
a
r
d
-
t
o
-
r
i
s
k
 
r
a
t
i
o
 
f
o
r
 
a
l
l
 
a
s
s
e
t
s
 
e
q
u
a
l
 
t
o
 
t
h
e
m
a
r
k
e
t
 
r
i
s
k
 
p
r
e
m
i
u
m
 
r
e
s
u
l
t
s
 
i
n
 
a
n
 
e
q
u
a
t
i
o
n
 
k
n
o
w
n
 
a
s
 
t
h
e
c
a
p
i
t
a
l
 
a
s
s
e
t
 
p
r
i
c
i
n
g
 
m
o
d
e
l
.
 
44
 
The Security Market Line, III.
 
 
T
h
e
 
C
a
p
i
t
a
l
 
A
s
s
e
t
 
P
r
i
c
i
n
g
 
M
o
d
e
l
 
(
C
A
P
M
)
 
i
s
 
a
 
t
h
e
o
r
y
 
o
f
r
i
s
k
 
a
n
d
 
r
e
t
u
r
n
 
f
o
r
 
s
e
c
u
r
i
t
i
e
s
 
i
n
 
a
 
c
o
m
p
e
t
i
t
i
v
e
 
c
a
p
i
t
a
l
m
a
r
k
e
t
.
 
 
 
 
The CAPM shows that 
E(R
i
)
 depends on:
R
f
, the pure time value of money.
E(R
M
) – R
f
, the reward for bearing systematic risk.
i
, the amount of systematic risk.
 
45
 
The Security Market Line, IV.
 
46
 
The Security Market Line (SML)
 
47
 
Risk and Return Summary, I.
 
48
 
Risk and Return Summary, II.
 
49
 
A Closer Look at Beta
 
 
R – E(R) = m
 + 
, where 
m
 is the systematic portion of
the unexpected return.
m
 = 
 
 [
R
M
 
 
E(R
M
)
]
So, 
R – E(R) = 
 
 [
R
M
 
 
E(R
M
)
] + 
In other words:
A high-Beta security is simply one that is relatively sensitive to
overall market movements
A low-Beta security is one that is relatively insensitive to overall
market movements.
 
50
 
Decomposition of Total Returns
 
51
 
Unexpected Returns and Beta
 
52
 
Where Do Betas Come From?
 
 
A security’s Beta depends on:
How closely correlated the security’s return is with the overall
market’s return, and
How volatile the security is relative to the market.
A security’s Beta is equal to the correlation multiplied by
the ratio of the standard deviations.
 
 
 
53
Algebraically, beta can be expressed as
follows:
 
54
 
Where Do Betas Come From?
 
55
 
Using a Spreadsheet to Calculate Beta
 
56
 
Beta Measures Relative Movement
 
 
A security with a beta of 1 is expected to move, on average, with the
market.
In this case, the characteristic line would have  a 45 degree angle, or a slope of 1.
This slope means that if the market goes up, say, 3%, we expect the stock to go up 3%.
In mathematics, we measure slope as “the rise over the run.”
So, if the market return is the “x data” and the stock return is the “y data,” the slope is the
beta of the security.
 
Apply this method to the scatter plot on the next slide. What do you
think the beta is?
When the market has a 10% return, the security return is slightly less than 10%.
The characteristic line suggests that the beta for this security is less than 1. Why?
You might recall from your statistics class an alternative method for
estimating a “line of best fit,” a simple linear regression.
We  regress the returns of the security (y data) on the returns of the market (x data).
Excel has a built-in regression function.
The output has an estimate of the “Market Returns” coefficient, i.e., the slope.
The highlighted “Market Returns” coefficient is the beta estimate.
 
57
 
Another Way to Calculate Beta
(The Characteristic Line)
 
58
 
Build a Beta
 
59
 
Why Do Betas Differ?
 
 
Betas are estimated from actual data. Different sources
estimate differently, possibly using different data.
F
o
r
 
d
a
t
a
,
 
t
h
e
 
m
o
s
t
 
c
o
m
m
o
n
 
c
h
o
i
c
e
s
 
a
r
e
 
t
h
r
e
e
 
t
o
 
f
i
v
e
 
y
e
a
r
s
 
o
f
 
m
o
n
t
h
l
y
d
a
t
a
,
 
o
r
 
a
 
s
i
n
g
l
e
 
y
e
a
r
 
o
f
 
w
e
e
k
l
y
 
d
a
t
a
.
To measure the overall market, the S&P 500 stock market index is
commonly used.
The calculated betas can be adjusted for various statistical reasons.
And betas are time-sensitive (next slide)
T
h
e
 
b
o
t
t
o
m
-
l
i
n
e
 
l
e
s
s
o
n
:
 
W
e
 
a
r
e
 
i
n
t
e
r
e
s
t
e
d
 
i
n
 
k
n
o
w
i
n
g
w
h
a
t
 
t
h
e
 
b
e
t
a
 
o
f
 
t
h
e
 
s
t
o
c
k
 
w
i
l
l
 
b
e
 
i
n
 
t
h
e
 
f
u
t
u
r
e
,
 
b
u
t
 
w
e
e
s
t
i
m
a
t
e
 
b
e
t
a
s
 
u
s
i
n
g
 
h
i
s
t
o
r
i
c
a
l
 
d
a
t
a
.
Anytime we use the past to predict the future, there is the
danger of a poor estimate.
 
60
 
Variation of Beta in Time
 
61
 
Important General Risk-Return Principles
 
 
Investing has two dimensions: risk and return.
 
It is inappropriate to look at the total risk of an individual
security.
 
It is appropriate to look at how an individual security
contributes to the risk of the overall portfolio
 
Risk can be decomposed into nonsystematic and
systematic risk.
 
Investors will be compensated only for systematic risk.
 
62
 
Extending CAPM
 
 
The CAPM has a stunning implication:
What you earn on your portfolio depends only on the level of
systematic risk that you bear
As a diversified investor, you do not need to worry about total
risk, only systematic risk.
 
B
u
t
,
 
d
o
e
s
 
e
x
p
e
c
t
e
d
 
r
e
t
u
r
n
 
d
e
p
e
n
d
 
o
n
l
y
 
o
n
 
B
e
t
a
?
 
O
r
,
d
o
 
o
t
h
e
r
 
f
a
c
t
o
r
s
 
c
o
m
e
 
i
n
t
o
 
p
l
a
y
?
 
The above bullet point is a hotly debated question.
 
63
Criticism toward CAPM and Conclusion
 
 
The statistical tests have problems that make empirical
verification virtually impossible.
 
Investors seem to be concerned with both market risk and
stand-alone risk.  Therefore, the SML may not produce a
correct estimate of the expected return.
 
CAPM/SML concepts are based on expectations and future
risk, yet betas are calculated using historical data.  A
company’s historical data may not reflect investors’
expectations about future riskiness.
 
Other models are being developed that will one day replace
the CAPM, but it still provides a good framework for thinking
about risk and return.
 
 
64
 
The Fama-French Three-Factor Model
 
 
Professors Gene Fama and Ken French argue that two
additional factors should be added.
 
In addition to beta, two other factors appear to be useful
in explaining the relationship between risk and return.
Size, as measured by market capitalization
The book value to market value ratio, i.e., B/M
 
Whether these two additional factors are truly sources of
systematic risk is still being debated.
 
65
 
The Size Effect:
Being Small Means a Better Performance!
 
66
 
The Book-to-Market Ratio Effect
 
67
 
Returns from 25 Portfolios Formed
on Size and Book-to-Market
1926-2006, 1927-2014
 
Note that the portfolio containing the smallest cap and
the highest book-to-market have had the highest returns.
 
68
 
 
A risk that affects a limited number of securities is known as
unsystematic risk.
A
)
 
T
r
u
e
B
)
 
F
a
l
s
e
 
 
The time value of money is measured by the rate of return on the U.S.
Treasury bill.
A
)
 
T
r
u
e
B
)
 
F
a
l
s
e
 
 
The reward for bearing risk depends on _____ risk.
A
)
 
u
n
i
q
u
e
B
)
 
s
y
s
t
e
m
a
t
i
c
C
)
 
a
s
s
e
t
-
s
p
e
c
i
f
i
c
D
)
 
d
i
v
e
r
s
i
f
i
a
b
l
e
E
)
 
c
o
m
p
a
n
y
 
69
 
 
An unexpected return is most apt to result from which
one of these events?
A
)
 
A
 
f
i
r
m
'
s
 
p
r
i
c
e
-
e
a
r
n
i
n
g
s
 
r
a
t
i
o
 
w
a
s
 
t
h
e
 
s
a
m
e
 
a
s
 
t
h
e
 
p
r
i
o
r
y
e
a
r
'
s
 
r
a
t
i
o
.
B
)
 
A
 
f
i
r
m
 
a
n
n
o
u
n
c
e
d
 
i
t
s
 
q
u
a
r
t
e
r
l
y
 
d
i
v
i
d
e
n
d
 
w
o
u
l
d
 
c
o
n
t
i
n
u
e
t
o
 
b
e
 
p
a
i
d
.
C
)
 
C
o
r
p
o
r
a
t
e
 
i
n
c
o
m
e
 
t
a
x
e
s
 
r
o
s
e
 
a
c
c
o
r
d
i
n
g
 
t
o
 
t
h
e
 
t
a
x
 
l
a
w
a
p
p
r
o
v
e
d
 
t
w
o
 
y
e
a
r
s
 
a
g
o
.
D
)
 
A
 
f
i
r
m
 
i
n
c
r
e
a
s
e
d
 
i
t
s
 
a
n
n
u
a
l
 
d
i
v
i
d
e
n
d
 
b
y
 
t
h
e
 
s
a
m
e
p
e
r
c
e
n
t
a
g
e
 
a
s
 
i
n
 
p
r
e
v
i
o
u
s
 
y
e
a
r
s
.
E
)
 
T
h
e
 
e
a
r
n
i
n
g
s
 
o
f
 
a
 
f
i
r
m
 
d
e
c
l
i
n
e
d
 
d
u
e
 
t
o
 
a
n
 
i
n
d
u
s
t
r
i
a
l
a
c
c
i
d
e
n
t
.
70
 
 
Which one of the following is most likely an unsystematic risk?
A
)
 
a
 
c
h
a
n
g
e
 
i
n
 
t
h
e
 
p
r
i
c
e
 
o
f
 
e
l
e
c
t
r
i
c
i
t
y
B
)
 
a
 
m
a
r
k
e
t
 
s
h
o
r
t
a
g
e
 
o
f
 
o
i
l
C
)
 
t
h
e
 
r
a
p
i
d
 
d
e
c
r
e
a
s
e
 
i
n
 
t
h
e
 
r
a
t
e
 
o
f
 
G
D
P
 
g
r
o
w
t
h
D
)
 
a
 
l
a
b
o
r
 
s
t
r
i
k
e
 
a
t
 
a
 
r
e
t
a
i
l
 
s
t
o
r
e
E
)
 
a
n
 
i
n
c
r
e
a
s
e
 
i
n
 
t
h
e
 
c
o
s
t
 
o
f
 
h
e
a
l
t
h
 
i
n
s
u
r
a
n
c
e
 
 
A security which is overvalued will lie _____ and a security
which is correctly valued will lie _____.
A
)
 
a
b
o
v
e
 
t
h
e
 
s
e
c
u
r
i
t
y
 
m
a
r
k
e
t
 
l
i
n
e
 
(
S
M
L
)
;
 
o
n
 
t
h
e
 
h
o
r
i
z
o
n
t
a
l
 
a
x
i
s
B
)
 
a
b
o
v
e
 
t
h
e
 
S
M
L
;
 
o
n
 
t
h
e
 
S
M
L
C
)
 
b
e
l
o
w
 
t
h
e
 
S
M
L
;
 
o
n
 
t
h
e
 
h
o
r
i
z
o
n
t
a
l
 
a
x
i
s
D
)
 
b
e
l
o
w
 
t
h
e
 
S
M
L
;
 
o
n
 
t
h
e
 
S
M
L
E
)
 
t
o
 
t
h
e
 
r
i
g
h
t
 
o
f
 
t
h
e
 
S
M
L
;
 
t
o
 
t
h
e
 
l
e
f
t
 
o
f
 
t
h
e
 
S
M
L
71
 
 
What is the slope of the security market line if the U. S. Treasury bill
has a return of 4.5 percent and the market has a return of 12.2
percent?
A
)
 
5
.
4
5
 
p
e
r
c
e
n
t
B
)
 
6
.
0
0
 
p
e
r
c
e
n
t
C
)
 
7
.
2
8
 
p
e
r
c
e
n
t
D
)
 
7
.
7
0
 
p
e
r
c
e
n
t
E
)
 
7
.
8
5
 
p
e
r
c
e
n
t
 
 
Jensen and Sons common stock has an expected return of 14.8
percent. The risk-free rate is 2.8 percent and the market risk
premium is 6.4 percent. What is the beta on Jensen and Sons stock?
A
)
 
1
.
4
0
8
B
)
 
1
.
7
5
0
C
)
 
1
.
8
7
5
D
)
 
1
.
9
3
2
E
)
 
1
.
9
8
5
72
 
 
You would like to invest $40,000 in a stock with a beta of
1.68. How much would you need to invest in U.S.
Treasury bills to create a portfolio containing these two
securities if you want the portfolio beta equal to the
market beta?
A
)
 
$
2
4
,
8
0
0
B
)
 
$
2
7
,
2
0
0
C
)
 
$
5
7
,
9
0
0
D
)
 
$
6
4
,
8
0
0
E
)
 
$
6
7
,
2
0
0
 
 
73
Slide Note
Embed
Share

This chapter delves into the concepts of risk and return in financial markets, exploring the relationship between expected and unexpected returns, systematic and unsystematic risk, and the Security Market Line. It also discusses the impact of announcements and news on stock returns, distinguishing between systematic and unsystematic components. Through examples and explanations, the chapter aims to provide a comprehensive understanding of how risk and return are interconnected in the world of finance.

  • Risk and Return
  • Financial Markets
  • Systematic Risk
  • Unsystematic Risk
  • Security Market Line

Uploaded on Jul 29, 2024 | 1 Views


Download Presentation

Please find below an Image/Link to download the presentation.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.

You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.

E N D

Presentation Transcript


  1. Chapter 12 Return, Risk, and the Security Market Line

  2. Learning Objectives Our goal in this chapter is to define risk more precisely, and discuss how to measure it. In addition, we will quantify the relation between risk and return in financial markets. More specifically, our goal is to understand 1. The difference between expected and unexpected returns. 2. The difference between systematic risk and unsystematic risk. 3. The security market line and the capital asset pricing model. 4. The importance of beta. 2

  3. Expected and Unexpected Returns The return on any stock traded in a financial market is composed of two parts. The normal, or expected, part of the return is the return that investors predict or expect. The uncertain, or risky, part of the return comes from unexpected information revealed during the year. Expected = Unexpected + Total Return Return Return Total = Unexpected Return Return Expected - Return E(R) - R = U 3

  4. Announcements and News Firms make periodic announcements about events that may significantly impact the profits of the firm. Earnings Product development Personnel The impact of an announcement depends on how much of the announcement represents new information. When the situation is not as bad as previously thought, what seems to be bad news is actually good news. When the situation is not as good as previously thought, what seems to be good news is actually bad news. News about the future is what really matters. Market participants factor predictions about the future into the expected part of the stock return. Announcement = Expected News + Surprise News 4

  5. Systematic and Unsystematic Risk Systematic risk is risk that influences a large number of assets. Also called market risk. Unsystematic risk is risk that influences a single company or a small group of companies. Also called unique riskor firm-specific risk. Total risk = Systematic risk + Unsystematic risk 5

  6. Pop Quiz: Systematic Risk or Unsystematic Risk? The government announces that inflation unexpectedly jumped by 2 percent last month. Systematic Risk One of Big Widget s major suppliers goes bankruptcy. Unsystematic Risk The head of accounting department of Big Widget announces that the company s current ratio has been severely deteriorating. Unsystematic Risk Congress approves changes to the tax code that will increase the top marginal corporate tax rate. Systematic Risk 6

  7. Systematic and Unsystematic Components of Return Recall: R E(R) = U = Systematic portion+ Unsystematic portion = m + R E(R) = m + 7

  8. Diversification and Risk In a large portfolio: Some stocks will go up in value because of positive company- specific events, while Others will go down in value because of negative company- specific events. Unsystematic risk is essentially eliminated by diversification, so a portfolio with many assets has almost no unsystematic risk. Unsystematic risk is also called diversifiablerisk. Systematic risk is also called non-diversifiablerisk. 8

  9. The Systematic Risk Principle What determines the size of the risk premium on a risky asset? The systematic risk principle states: The expected return on an asset depends only on its systematic risk. So, no matter how much total risk an asset has, only the systematic portion is relevant in determining the expected return (and the risk premium) on that asset. 9

  10. Measuring Systematic Risk To be compensated for risk, the risk has to be special. Unsystematic risk is not special. Systematic risk is special. The Beta coefficient ( ) measures the relative systematic risk of an asset. Assets with Betas larger than 1.0 have more systematic risk than average. Assets with Betas smaller than 1.0 have less systematic risk than average. Because assets with larger betas have greater systematic risks, they will have greater expected returns. Note that not all Betas are created equally. 10

  11. Betas with Respect to the S&P 500 for Individual Stocks (based on monthly data for 2004 2008) 11

  12. Finding a Beta on the Web 12

  13. Portfolio Betas The total risk of a portfolio has no simple relation to the total risk of the assets in the portfolio. Recall the variance of a portfolio equation For two assets, you need two variances and the covariance. For four assets, you need four variances, and six covariances. In contrast, a portfolio Beta can be calculated just like the expected return of a portfolio. That is, you can multiply each asset s Beta by its portfolio weight and then add the results to get the portfolio s Beta. 13

  14. Example: Calculating a Portfolio Beta Using Value Line data from Table 12.1, we see Beta for Southwest Airlines (LUV) is 1.05 Beta for General Motors (GM) 1.45 You put half your money into LUV and half into GM. What is your portfolio Beta? = + .50 .50 p LUV GM .50 = + 1.05 .50 1.45 1.25 = 12-14

  15. Capital Asset Pricing Model (CAPM) Now, we will go back to the Markowitz's efficient market frontier. In order to derive the CAPM, Capital Market Line (CML), Security Market Line (SML). Here, we will try to derive the security market line (SML), which is a linear line characterized with risk-free rate and the market portfolio. A series of graphs explain all . 15

  16. Efficient Frontier with Ten Stocks Versus Three Stocks 16

  17. Risk-Free Saving and Borrowing Risk can also be reduced by investing a portion of a portfolio in a risk-free investment, like T-Bills. However, doing so will likely reduce the expected return. On the other hand, an aggressive investor who is seeking high expected returns might decide to borrow money to invest even more in the stock market. 17

  18. Investing in Risk-Free Securities Consider an arbitrary risky portfolio and the effect on risk and return of putting a fraction of the money in the portfolio, while leaving the remaining fraction in risk-free Treasury bills. The expected return would be: = = + + [ ] (1 ) x r [ ] E R xE R xP f P f r ( [ x E R ] ) f r P 18

  19. Investing in Risk-Free Securities (cont'd) The standard deviation of the portfolio would be calculated as: = + + 2 2 [ ] (1 ) x Var r ( ) f ( ) 2(1 ) x xCov r R ( , ) SD R x Var R xP P f P = = 2 ( ) ) x Var R xSD R 0 P ( P Note: The standard deviation is only a fraction of the volatility of the risky portfolio, based on the amount invested in the risky portfolio. 19

  20. The RiskReturn Combinations from Combining a Risk- Free Investment and a Risky Portfolio 20

  21. The Tangent or Efficient Portfolio 21

  22. The Capital Market Line (CML) 22

  23. The Market Portfolio Because portfolio M lies at the point of tangency, it has the highest portfolio possibility line So, everybody will want to invest in Portfolio M and borrow or lend to be somewhere on the straight line. This line is called the Capital Market Line (CML). Therefore this portfolio must include ALL RISKY ASSETS not only U.S. common stocks but also all risky assets, such as Non-U.S. stocks, options, real estate, coins, and art. 23

  24. Continued Because the market is in equilibrium, all assets are included in this portfolio in proportion to their market value Because it contains all risky assets, it is a completely diversified portfolio, which means that all the unique risk of individual assets (unsystematic risk) is diversified away All portfolios on the CML are perfectly positively correlated with each other and with the completely diversified market Portfolio M A completely diversified portfolio would have a correlation with the market portfolio of +1.00 24

  25. The CML and the Separation Theorem Investors preferring more risk might borrow funds at the RFR and invest everything in the market portfolio The decision of both investors is to invest in portfolio M along the CML (the investment decision) ( ) E R port CML B M A RFR port 25

  26. The Security Market Line There is a linear relationship between a stock s beta and its expected return (See figure on next slide). The security market line (SML) is graphed as the line through the risk-free investment and the market. According to the CAPM, if the expected return and beta for individual securities are plotted, they should all fall along the SML. 26

  27. The Capital Market Line and the Security Market Line 27

  28. The Capital Market Line and the Security Market Line The CML depicts portfolios combining the risk-free investment and the efficient portfolio, and shows the highest expected return that we can attain for each level of volatility. According to the CAPM, the market portfolio is on the CML and all other stocks and portfolios contain diversifiable risk and lie to the right of the CML, as illustrated for Exxon Mobil (XOM). 28

  29. The Capital Market Line and the Security Market Line The SML shows the expected return for each security as a function of its beta with the market. According to the CAPM, the market portfolio is efficient, so all stocks and portfolios should lie on the SML. 29

  30. Beta and the Risk Premium, I. Consider a portfolio made up of asset A and a risk-free asset. For asset A, E(RA) = 16% and A = 1.6 The risk-free rate Rf = 4%. Note that for a risk-free asset, = 0 by definition. We can calculate some different possible portfolio expected returns and betas by changing the percentages invested in these two assets. Note that if the investor borrows at the risk-free rate and invests the proceeds in asset A, the investment in asset A will exceed 100%. 30

  31. Beta and the Risk Premium, II. Portfolio Expected Return % of Portfolio in Asset A Portfolio Beta 0% 4 0.0 25 7 0.4 50 10 0.8 75 13 1.2 100 16 1.6 125 with borrowing 19 2.0 150 with borrowing 22 2.4 31

  32. Portfolio Expected Returns and Betas for Asset A 32

  33. The Reward-to-Risk Ratio Notice that all the combinations of portfolio expected returns and betas fall on a straight line. Slope (Rise over Run): ( E = ) R R 16% 4% = = A f 7.50% 1.6 A What this tells us is that asset A offers a reward-to-risk ratio of 7.50%. In other words, asset A has a risk premium of 7.50% per unit of systematic risk. 33

  34. Performance Evaluation Measures The Sharpe Ratio The Sharpe ratio is a reward-to-risk ratio that focuses on total risk. It is computed as a portfolio s risk premium divided by the standard deviation of the portfolio s return. R R p f = Sharpe ratio p 34

  35. Performance Evaluation Measures The Treynor Ratio The Treynor ratio is a reward-to-risk ratio that looks at systematic risk only. It is computed as a portfolio s risk premium divided by the portfolio s beta coefficient. R R p f = Treynor ratio p 35

  36. The Basic Argument, I. Recall that for asset A: E(RA) = 16% and A = 1.6 Suppose there is a second asset, asset B. For asset B: E(RB) = 12% and A = 1.2 Which investment is better, asset A or asset B? Asset A has a higher expected return Asset B has a lower systematic risk measure 36

  37. The Basic Argument, II As before with Asset A, we can calculate some different possible portfolio expected returns and betas by changing the percentages invested in asset B and the risk-free rate. % of Portfolio in Asset B 0% 25 50 75 100 125 150 Portfolio Expected Return 4 6 8 10 12 14 16 Portfolio Beta 0.0 0.3 0.6 0.9 1.2 1.5 1.8 12-37

  38. Portfolio Expected Returns and Betas for Asset B 38

  39. Portfolio Expected Returns and Betas for Both Assets 39

  40. The Fundamental Result, I. The situation we have described for assets A and B cannot persist in a well-organized, active market Investors will be attracted to asset A (and buy A shares) Investors will shy away from asset B (and sell B shares) This buying and selling will make The price of A shares increase The price of B shares decrease This price adjustment continues until the two assets plot on exactly the same line. ( ) ( ) E R R E R R That is, until: = A f B f A B 40

  41. The Fundamental Result, II. In general The reward-to-risk ratio must be the same for all assets in a competitive financial market. If one asset has twice as much systematic risk as another asset, its risk premium will simply be twice as large. Because the reward-to-risk ratio must be the same, all assets in the market must plot on the same line. 41

  42. The Fundamental Result, III. 42

  43. The Security Market Line (SML) The Security market line (SML) is a graphical representation of the linear relationship between systematic risk and expected return in financial markets. For a market portfolio, ( ) ( ) E R R E R R = = M f M f 1 M ( ) = E R R M f 43

  44. The Security Market Line, II. The term E(RM) Rf is often called the market risk premium because it is the risk premium on a market portfolio. ( ) E R R ( ) = i f E R R For any asset i in the market: M f i ( ) ( ) = + E R R E R R i f M f i Setting the reward-to-risk ratio for all assets equal to the market risk premium results in an equation known as the capital asset pricing model. 44

  45. The Security Market Line, III. The Capital Asset Pricing Model (CAPM) is a theory of risk and return for securities in a competitive capital market. ( ) ( ) = + E R R E R R i f M f i The CAPM shows that E(Ri) depends on: Rf, the pure time value of money. E(RM) Rf, the reward for bearing systematic risk. i, the amount of systematic risk. 45

  46. The Security Market Line, IV. 46

  47. The Security Market Line (SML) 47

  48. Risk and Return Summary, I. 48

  49. Risk and Return Summary, II. 49

  50. A Closer Look at Beta R E(R) = m + , where m is the systematic portion of the unexpected return. m = [RM E(RM)] So, R E(R) = [RM E(RM)] + In other words: A high-Beta security is simply one that is relatively sensitive to overall market movements A low-Beta security is one that is relatively insensitive to overall market movements. 50

More Related Content

giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#