Session 3 - Behavioral Finance Flashcards
(83 cards)
Traditional vs Behavioural
1/ traditional
– normative (ideal) how individuals and markets should behave
- grounded in neoclassical economics
- indvls are: risk-averse, self-interested, utility maximized
- markets are: efficient, prices incorporate and reflect all information
2/ behavioral
– descriptive (actual)
– observed indvl and markets behaviors
– grounded in psychology
– neither assume rationality nor efficient markets
Behavioral indvl or market focus
- 1/ individual focus (micro - BFMI)
- biases/errors impact financial decisions
- 2/ market focus (macro - BFMA)
- defects and describes market anomalies
- markets are subject to behavioral effects
Traditional view
- rational
- make decisions consistent with utility theory
- revise expectations consistent with Bayes’ formula
- self-interested, risk-averse, access to perfect information, process
all available information in an unbiased way
Utility under Traditional View and Basic Axioms underneath
- max PV of utility subject to a present value budget constraint
- basic axioms:
• completeness – well-defined preferences, ranked
• transitivity – 𝐀≻𝐁,𝐁≻𝐂 ⇒𝐀≻𝐂
• independence – 𝐀≻𝐁 ⇒ 𝐀 + 𝐱𝐂≻𝐁+ 𝐱𝐂
• continuity - 𝐀≻𝐁,𝐁≻𝐂⇒𝐬𝐨𝐦𝐞𝐀+𝐂~𝐁
Bayes
– given new information, decision maker is assumed to update beliefs about probabilities
𝐏(𝐔𝟏|𝐑) = 𝐏(𝐑|𝐔𝟏)/𝐏(𝐑) 𝐱 𝐏(𝐔𝟏)
Rational Economic Man
– will try to obtain the highest possible economic well being (utility) given
- budget constraints
- available information
- will not consider the well-being of others
- Perfect Rationality, Perfect Self-Interest, Perfert Information
Perfect Rationality
ability to reason and make beneficial judgments at all times
Perfect Self-Interest
humans are perfectly selfish
Perfect Information
all investors know all things at all times
∴ will always make the best decisions
Risk-Aversion
- utility functions are concave and show the diminishing marginal utility of wealth
- risk evaluation reference-dependent
- depends on the wealth level and circumstances of the decision-maker
Bounded rationality (under Behavioral view)
– choices may be rational but are subject to the limitations of knowledge & cognitive capacity (challenges perfect information)
Inner conflicts (under Behavioral view)
- short-term vs. long-term goals
- individual vs. social goals
Altruism
- challenges perfect self-interest
Prospect Theory/ Kahneman & Tuersky (79)
- an alternative to expected utility theory
- 2 phases to making a choice
- preference for risk-seeking or risk-averse behavior determined by attitudes towards gains & losses
- attitudes are defined relative to a reference point and not total wealth
- people tend to be risk-averse when there is a moderate to high probability of gains or a low probability of losses
- risk-seeking when there is a low probability of gains or a high probability of losses
Decision theory
– normative, concerned with identifying the ideal decision
- assumes decision-maker is fully informed, is able to make quantitative calculations with accuracy, and is perfectly rational
Simon (57) and satisficing
- people are not fully rational when making decisions and do not necessarily optimize but rather satisfice
- people have informational, intellectual, and computational limitations
- stop when they have arrived at a satisfactory decision
Satisfice (satisfy & suffice)
- cost & time of optimal outcomes too high
- complexity builds
- humans have ‘bounded rationality’
- decisions need only be adequate, not optimal
- individuals lack the cognitive resources to arrive at optimal solutions
e. g. - typically do not know relevant probabilities
- can rarely identify or evaluate all outcomes
- have weak & unreliable memories
Traditional at the market level
– prices incorporate and reflect all relevant info.
- individual-level ⇒ market participants are rational economic beings acting in their own self-interest and making optimal decisions
- when new relevant info. appears, expectations are updated and freely available to all participants
∴ markets are efficient
– prices are correct (i.e. = IV)
– no abnormal returns (i.e. risk-adjusted)
Weak form market efficiency
- no past price or volume info. can be used to generate abnormal returns
- technical analysis will not generate excess return
Semi-strong market efficiency
- all publicly available info. is reflected in prices - both TA & fund. the analysis will not generate excess r.
Strong Form market efficiency
- all public & private info is fully reflected in prices
- inside info will not generate excess return
Challenges to efficient market hypothesis
1) fundamental (e.g. small-cap & value companies)
2) technical
3) calendar (e.g. January effect)
Portfolio construction under the Traditional approach
– mean-variance efficient
⇒ the optimal portfolio given the investor’s risk tolerance
4 Approaches under Behavioural
1/ a behavioral approach to Consumption & Savings/
2/ a behavioral approach to asset pricing/
3/ behavioral portfolio theory/
4/ adaptive markets hypothesis/ (AMH