Презентация на тему Efficient Market Hypothesis

the book show how to evaluate investment projects according

to NPV criterion.
The next five chapters concern financing decisions.

much debt and equity to sell
When (or if) to

pay dividends
When to sell debt and equity
Just as we can use NPV criteria to evaluate investment decisions, we can use NPV to evaluate financing decisions.

suggests that it is hard to fool investors consistently.
Reduce

Costs or Increase Subsidies
Certain forms of financing have tax advantages or carry other subsidies.
Create a New Security
Sometimes a firm can find a previously-unsatisfied clientele and issue new securities at favourable prices.
In the long-run, this value creation is relatively small, however.

capital market is one in which stock prices fully

reflect available information.
The EMH has implications for investors and firms.
Since information is reflected in security prices quickly, knowing information when it is released does an investor no good.
Firms should expect to receive the fair value for securities that they sell. Firms cannot profit from fooling investors in an efficient market.

Efficient and Inefficient Markets
Stock Price
-30 -20 -10 0 +10 +20 +30
Days before (-) and

after (+) announcement

Efficient market response to “good news”

Overreaction to “good news” with reversion

Delayed response to “good news”

Efficient and Inefficient Markets
Stock Price
-30 -20 -10 0 +10 +20 +30
Days before (-) and

after (+) announcement

Efficient market response to “bad news”

Overreaction to “bad news” with reversion

Delayed response to “bad news”

reflect all information found in past prices and volume.
Semi-Strong

Form
Security prices reflect all publicly available information.
Strong Form
Security prices reflect all information—public and private.

found in past prices and volume.
If the weak form

of market efficiency holds, then technical analysis is of no value.
Often weak-form efficiency is represented as
Pt = Pt-1 + Expected return + random error t
Since stock prices only respond to new information, which by definition arrives randomly, stock prices are said to follow a random walk.

eliminate any profit opportunity associated with stock price patterns.
If

it were possible to make big money simply by finding “the pattern” in the stock price movements, everyone would do it and the profits would be competed away.

available information.
Publicly available information includes:
Historical price and volume information
Published

accounting statements.
Information found in annual reports.

and private.
Strong form efficiency incorporates weak and semi-strong form

efficiency.
Strong form efficiency says that anything pertinent to the stock and known to at least one investor is already incorporated into the security’s price.

EMH has been based on a misunderstanding of what

the hypothesis says and does not say.

can throw darts to select stocks.
This is almost, but

not quite, true.
An investor must still decide how risky a portfolio he wants based on risk aversion and the level of expected return.
Prices are random or uncaused.
Prices reflect information.
The price CHANGE is driven by new information, which by definition arrives randomly.
Therefore, financial managers cannot “time” stock and bond sales.

extensive, and in large measure it is reassuring to

advocates of the efficiency of markets.
Studies fall into three broad categories:
Are changes in stock prices random? Are there profitable “trading rules”?
Event studies: does the market quickly and accurately respond to new information?
The record of professionally managed investment firms.

tell?
Many psychologists and statisticians believe that most people want

to see patterns even when faced with pure randomness.
People claiming to see patterns in stock price movements are probably seeing optical illusions.
A matter of degree
Even if we can spot patterns, we need to have returns that beat our transactions costs.
Random stock price changes support weak-form efficiency.

chart to see a different random series. With different

patterns, you may believe that you can predict the next value in the series—even though you know it is random.

one type of test of the semi-strong form of

market efficiency.
This form of the EMH implies that prices should reflect all publicly available information.
To test this, event studies examine prices and returns over time—particularly around the arrival of new information.
Test for evidence of underreaction, overreaction, early reaction, delayed reaction around the event.

determine if they are abnormal by taking into account

what the rest of the market did that day.
The Abnormal Return on a given stock for a particular day can be calculated by subtracting the market’s return on the same day (RM) from the actual return (R) on the stock for that day:
AR= R – Rm
The abnormal return can be calculated using the Market Model approach:
AR= R – (α + βRm)

news”
S.H. Szewczyk, G.P. Tsetsekos, and Z. Santout “Do Dividend

Omissions Signal Future Earnings or Past Earnings?” Journal of Investing (Spring 1997)

has been applied to a large number of events

including:
Dividend increases and decreases
Earnings announcements
Mergers
Capital spending
New issues of stock
The studies generally support the view that the market is semistrong-form efficient.
In fact, the studies suggest that markets may even have some foresight into the future—in other words, news tends to leak out in advance of public announcements.

Event Issue
Possible Model Misspecification

semistrong-form efficient, then no matter what publicly available information

mutual-fund managers rely on to pick stocks, their average returns should be the same as those of the average investor in the market as a whole.
We can test efficiency by comparing the performance of professionally managed mutual funds with the performance of a market index.

and Robert F. Stambaugh, “Evaluating and Investing in Equity

Mutual Funds,” unpublished paper, Graduate School of Business, University of Chicago (March 2000).

studies of strong-form market efficiency investigates insider trading.
A number

of studies support the view that insider trading is abnormally profitable.
Thus, strong-form efficiency does not seem to be substantiated by the evidence.

1987
The NYSE dropped between 20-percent and 25-percent and the

TSE dropped by more than 11-percent on a Monday following a weekend during which little surprising information was released.
Temporal Anomalies
Turn of the year, —month, —week.
For large-capitalization Canadian stocks there is no longer a day-of-the week effect.
Speculative Bubbles
Sometimes a crowd of investors can behave as a single squirrel.

in security prices quickly, investors should only expect to

obtain a normal rate of return.
Awareness of information when it is released does an investor little good. The price adjusts before the investor has time to act on it.
Firms should expect to receive the fair value for securities that they sell.
Fair means that the price they receive for the securities they issue is the present value.
Thus, valuable financing opportunities that arise from fooling investors are unavailable in efficient markets.

implications for corporate finance:
The price of a company’s stock

cannot be affected by a change in accounting.
Financial managers cannot “time” issues of stocks and bonds using publicly available information.
A firm can sell as many shares of stocks or bonds as it desires without depressing prices.
There is conflicting empirical evidence on all three points.

illusions, mirages, and apparent patterns in charts of stock

market returns.
The truth is less interesting.
There is some evidence against market efficiency:
Seasonality
Small versus Large stocks
Value versus Growth stocks
The tests of market efficiency are weak.