12E-Excel代写
时间:2023-04-16
Lecture 1: Behavioural Finance
Bodie, Kane and Marcus 12E McGraw Hill: Chapter 11, 12
Semester 1, 2023
Efficient Market Hypothesis (EMH)
• EMH says stock prices already reflect all available information
• A forecast about favorable future performance leads to favorable
current performance, as market participants rush to trade on
new information.
Result: Prices change until expected returns are exactly
commensurate with risk.
Efficient Market Hypothesis (EMH)
• New information is unpredictable; if it could be predicted, then
the prediction would be part of today’s information.
• Stock prices that change in response to new (unpredictable)
information also must move unpredictably.
• Stock price changes follow a random walk.
Figure 11.1 Cumulative Abnormal Returns Before
Takeover Attempts: Target Companies
Figure 11.2 Stock Price Reaction to CNBC Reports
Versions of the EMH
• Weak
• Semi-strong
• Strong
• All versions assert that prices should reflect available information
Types of Stock Analysis
• Technical Analysis - using prices and volume information to
predict future prices
- Success depends on a sluggish response of stock prices to
fundamental supply-and-demand factors.
- Weak form efficiency
• Relative strength
• Resistance levels
Types of Stock Analysis
• Fundamental Analysis - using economic and accounting information
to predict stock prices
- Try to find firms that are better than everyone else’s estimate.
- Try to find poorly run firms that are not as bad as the market thinks.
- Semi strong form efficiency and fundamental analysis
Behavioral Finance
Conventional Finance Behavioral Finance
• Prices are correct and
equal to intrinsic value
• Resources are
allocated efficiently
• Consistent with EMH
• What if investors don’t
behave rationally?
The Behavioral Critique
Two categories of irrationalities:
1. Investors do not always process information correctly
• Result: Incorrect probability distributions of future returns
2. Even when given a probability distribution of returns, investors
may make inconsistent or suboptimal decisions
• Result: They have behavioral biases
Rational decision
CHOICE 1
A. $1m with chance of winning of 100%
$1M x 100% = $1M
B. $1m with 89% chance; nothing with 1% chance and $5m with 10% chance
$1M x 89% + $0 x1% +$5M X 10% = $1.39M
CHOICE 2
A. $1m with 11% probability and $0 with 89% probability
$1M x 11% + $0 x 89% = $110,000
B. $5m with 10% probability and nothing with 90% probability.
$5M x 10% + $0 x 90% = $500,000
Errors in Information Processing: Misestimating
True Probabilities
1. Forecasting Errors: Too much weight is placed on recent
experiences
2. Overconfidence: Investors overestimate their abilities and the
precision of their forecasts
3. Conservatism: Investors are slow to update their beliefs and
under react to new information
4. Sample Size Neglect and Representativeness: Investors are too
quick to infer a pattern or trend from a small sample
Behavioral Biases: Examples
1. Framing
• How the risk is described, “risky losses” vs. “risky gains,” can
affect investor decisions
2. Mental Accounting
• Investors may segregate accounts or monies and take risks
with their gains that they would not take with their principal
Behavioral Biases: Examples
3. Regret Avoidance
• Investors blame themselves more when an unconventional or
risky bet turns out badly
4. Prospect Theory
• Conventional view: Utility depends on level of wealth
• Behavioral view: Utility depends on changes in current wealth
Limits to Arbitrage
• Behavioral biases would not matter if rational arbitrageurs could
fully exploit the mistakes of behavioral investors
• Fundamental Risk:
-“Markets can remain irrational longer than you can remain solvent”
- Intrinsic value and market value may take too long to converge
Limits to Arbitrage
• Implementation Costs:
- Transactions costs and restrictions on short selling can limit
arbitrage activity
• Model Risk:
- What if you have a bad model and the market value is actually
correct?
Technical Analysis: Trends and Corrections
• Momentum and moving averages
- The moving average is the average level of prices over a
given interval of time, where the interval is updated as time
passes
• Bullish signal: Market price breaks through the moving
average line from below, it is time to buy
• Bearish signal: When prices fall below the moving
average, it is time to sell
Figure 12.3 Moving Average for INTC
Technical Analysis: Relative Strength
• Relative strength
- Measures the extent to which a security has out- or
underperformed either the market as a whole or its particular
industry
- Pricing ratio implies outperformance
Security Price
Relative Strength=
Industry Price Index
Technical Analysis: Relative Strength
• Breadth
• Often measured as
the spread between
the number of
stocks that
advance and
decline in price
Technical Analysis: Sentiment Indicators
• Trin Statistic
Volume declining
Number declining
Trin =
Volume advancing
Number advancing
- Ratios above 1.0 are bearish
Technical Analysis: Sentiment Indicators
• Confidence Index
- The ratio of the average yield on 10 top-rated corporate
bonds divided by the average yield on 10 intermediate-
grade corporate bonds
- Higher values are bullish
Technical Analysis: Sentiment Indicators
• Put/Call Ratio
• Calls are the right to
buy
- A way to bet on rising
prices
• Puts are the right to
sell
- A way to bet on falling
prices
• A rising ratio may signal
investor pessimism and a
coming market decline
• Contrarian investors see a
rising ratio as a buying
opportunity
Thank you