Factor Models: Announcements, Surprises, and Expected Returns

Содержание

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11.1 Factor Models: Announcements, Surprises, and Expected Returns The return on

11.1 Factor Models: Announcements, Surprises, and Expected Returns

The return on any

security consists of two parts.
1) the expected or normal return: the return that shareholders in the market predict or expect
2) the unexpected or risky return: the portion that comes from information that will be revealed .
Examples of relevant information:
Statistics Canada figures (e.g., GNP)
A sudden drop in interest rates
News that the company’s sales figures are higher than expected
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11.1 Factor Models: Announcements, Surprises, and Expected Returns A way to

11.1 Factor Models: Announcements, Surprises, and Expected Returns

A way to write

the return on a stock in the coming month is:
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11.1 Factor Models: Announcements, Surprises, and Expected Returns Any announcement can

11.1 Factor Models: Announcements, Surprises, and Expected Returns

Any announcement can be

broken down into two parts, the anticipated or expected part and the surprise or innovation:
Announcement = Expected part + Surprise.
The expected part of any announcement is part of the information the market uses to form the expectation, R of the return on the stock.
The surprise is the news that influences the unanticipated return on the stock, U.
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11.2 Risk: Systematic and Unsystematic A systematic risk is any risk

11.2 Risk: Systematic and Unsystematic

A systematic risk is any risk that

affects a large number of assets, each to a greater or lesser degree.
An unsystematic risk is a risk that specifically affects a single asset or small group of assets.
Unsystematic risk can be diversified away.
Examples of systematic risk include uncertainty about general economic conditions, such as GNP, interest rates, or inflation.
On the other hand, announcements specific to a company, such as a gold mining company striking gold, are examples of unsystematic risk.
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11.2 Risk: Systematic and Unsystematic Systematic Risk; m Nonsystematic Risk; ε

11.2 Risk: Systematic and Unsystematic

Systematic Risk; m

Nonsystematic Risk; ε

n

σ

Total risk;

U

We can break down the risk, U, of holding a stock into two components: systematic risk and unsystematic risk:

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11.2 Risk: Systematic and Unsystematic Systematic risk is referred to as

11.2 Risk: Systematic and Unsystematic

Systematic risk is referred to as market

risk.
m influences all assets in the market to some extent.
Is specific to the company and unrelated to the specific risk of most other companies.
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11.3 Systematic Risk and Betas The beta coefficient, β, tells us

11.3 Systematic Risk and Betas

The beta coefficient, β, tells us the

response of the stock’s return to a systematic risk.
In the CAPM, β measured the responsiveness of a security’s return to a specific risk factor, the return on the market portfolio.

We shall now consider many types of systematic risk.

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11.3 Systematic Risk and Betas For example, suppose we have identified

11.3 Systematic Risk and Betas

For example, suppose we have identified three

systematic risks on which we want to focus:
Inflation
GDP growth
The dollar-pound spot exchange rate, S($,£)
Our model is:
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Systematic Risk and Betas: Example Suppose we have made the following

Systematic Risk and Betas: Example

Suppose we have made the following estimates:
βI

= -2.30
βGDP = 1.50
βS = 0.50.
Finally, the firm was able to attract a “superstar” CEO and this unanticipated development contributes 1% to the return.
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Systematic Risk and Betas: Example We must decide what surprises took

Systematic Risk and Betas: Example

We must decide what surprises took place

in the systematic factors.
If it was the case that the inflation rate was expected to be 3%, but in fact was 8% during the time period, then
FI = Surprise in the inflation rate
= actual – expected
= 8% - 3%
= 5%
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Systematic Risk and Betas: Example If it was the case that

Systematic Risk and Betas: Example

If it was the case that the

rate of GDP growth was expected to be 4%, but in fact was 1%, then
FGDP = Surprise in the rate of GDP growth
= actual – expected
= 1% - 4%
= -3%
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Systematic Risk and Betas: Example If it was the case that

Systematic Risk and Betas: Example

If it was the case that dollar-pound

spot exchange rate, S($,£), was expected to increase by 10%, but in fact remained stable during the time period, then
FS = Surprise in the exchange rate
= actual – expected
= 0% - 10%
= -10%
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Systematic Risk and Betas: Example Finally, if it was the case

Systematic Risk and Betas: Example

Finally, if it was the case that

the expected return on the stock was 8%, then
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11.4 Portfolios and Factor Models Now let us consider what happens

11.4 Portfolios and Factor Models

Now let us consider what happens to

portfolios of stocks when each of the stocks follows a one-factor model.
We will create portfolios from a list of N stocks and will capture the systematic risk with a 1-factor model.
The ith stock in the list have returns:
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Relationship Between the Return on the Common Factor & Excess Return

Relationship Between the Return on the Common Factor & Excess Return

Excess

return

The return on the factor F

If we assume that there is no unsystematic risk, then εi = 0

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Relationship Between the Return on the Common Factor & Excess Return

Relationship Between the Return on the Common Factor & Excess Return

Excess

return

The return on the factor F

If we assume that there is no unsystematic risk, then εi = 0

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Relationship Between the Return on the Common Factor & Excess Return

Relationship Between the Return on the Common Factor & Excess Return

Excess

return

The return on the factor F

Different securities will have different betas

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Portfolios and Diversification We know that the portfolio return is the

Portfolios and Diversification

We know that the portfolio return is the weighted

average of the returns on the individual assets in the portfolio:
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Portfolios and Diversification The return on any portfolio is determined by

Portfolios and Diversification

The return on any portfolio is determined by three

sets of parameters:

In a large portfolio, the third row of this equation disappears as the unsystematic risk is diversified away.

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Portfolios and Diversification So the return on a diversified portfolio is

Portfolios and Diversification

So the return on a diversified portfolio is determined

by two sets of parameters:
The weighed average of expected returns.
The weighted average of the betas times the factor F.

In a large portfolio, the only source of uncertainty is the portfolio’s sensitivity to the factor.

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11.5 Betas and Expected Returns The return on a diversified portfolio

11.5 Betas and Expected Returns

The return on a diversified portfolio is

the sum of the expected return plus the sensitivity of the portfolio to the factor.
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Relationship Between β & Expected Return The relevant risk in large

Relationship Between β & Expected Return

The relevant risk in large and

well-diversified portfolios is all systematic, because unsystematic risk is diversified away.
If shareholders are ignoring unsystematic risk, only the systematic risk of a stock can be related to its expected return.
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Relationship Between β & Expected Return Expected return β A B C D SML

Relationship Between β & Expected Return

Expected return

β

A

B

C

D

SML

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11.6 The Capital Asset Pricing Model and the Arbitrage Pricing Theory

11.6 The Capital Asset Pricing Model and the Arbitrage Pricing Theory

APT

applies to well diversified portfolios and not 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 without the assumption of the market portfolio.
APT can be extended to multifactor models.
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Multi-factor APT Example: A Canadian study (Otuteye, CIR 1991) with five

Multi-factor APT

Example: A Canadian study (Otuteye, CIR 1991)
with five factors:
the rate

of growth in industrial production
the changes in the slope of the term structure of interest rates
the default risk premium for bonds
inflation
The value-weighted return on the market portfolio (TSE 300)
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11.7 Empirical Approaches to Asset Pricing Both the CAPM and APT

11.7 Empirical Approaches to Asset Pricing

Both the CAPM and APT are

risk-based models. There are alternatives.
Empirical methods are based less on theory and more on looking for some regularities in the historical record.
Be aware that correlation does not imply causality.
Related to empirical methods is the practice of classifying portfolios by style e.g.,
Value portfolio
Growth portfolio