Section 4 Flashcards
what is the efficient market hypothesis?
The idea that security prices instantaneously reflect all available information
stock price reflects all available information - thus impossible to beat stock market in long run
fundamental analysis is pointless as past events are no use in terms of the randomness of the markets in future.
what if true does efficient market hypothesis mean?
That the market prices of securities will always equal the fair or fundamental values of those securities - and if they are not equal, then the difference is so small it cannot be exploited net of transactional costs
According to EMH when do prices change?
Only in response to new information, which is unpredictable. Therefore they follow a random path
According to EMH what should it be hard for active traders in financial markets to do?
Outperform passive investment strategies such as holding market indices
What are the three versions of EMH?
Weak form
Semi-strong form
Strong form
What is Weak form EMH?
security prices already reflect all information contained in the past history of market prices and volume. Hence technical analysis is a fruitless activity.
What is weak form EMH consistent with?
Random walk hypothesis which says that price changes are independent and suggests that one could only beat the market by using fundamental analysis or insider trading .
What is semi-strong form EMH?
all publicly available information about a firm (e.g. annual reports) is already contained in the stock price. Since past prices are a part of publicly available information, then weak form also holds.
at this level can’t use fundamental analysis
What does strong form EMH state?
A security price reflects all information relative to a firm, including information only available to company insiders. This is an unlikely and extreme case, as it would often involve the use of illegal inside info. If strong form holds then so does weak and semi-strong
no investor can beat over the long run over a risk adjusted basis
According to EMH what conditions are needed for an efficient market?
- A large number of rational, profit-maximising investors exist who actively participate in the market hence securities are valued rationally
- If some investors behave non-rationally then this is random and hence they cancel each other out - or rational arbitrageurs eliminate the influence of irrational agents
- Information is free and widely available, but if activities of irrational traders are correlated, then arbitrageurs act to eliminate the mispricing
what does EMH not negate?
that risker investors can win in short term
What acts as evidence against EMH?
- anomalies in the market e.g. seasonal variations / weekend effects
- announcements relating to earnings seem to have a relatively long-lasting impact on stock prices even after adjusting for risk and transactions costs
What are the basic tenets of standard finance / modern portfolio theory?
1) investors are rational
2) markets are efficient
3) investors design their portfolios according to mean-variance portfolio theory
4) expected returns depend on risk alone
What does behavioural finance suggest as alternatives to standard finance / modern portfolio theory?
1) Investors may not be rational and they are real people who make decisions in ways that may be considered normal but not necessarily rational
2) Markets are not efficient, even if they are hard to beat
3) Investors design portfolios according to rules of behavioural theory not mean variance portfolio theory
4) Expected returns are driven by a range of factors as well as risk
According to behavioural finance when making decisions what do investors do ?
- do not always process information correctly, and therefore do not infer the appropriate probability distribution of future returns
- often make inconsistent or systematically suboptimal decisions. This can lead to mispricing and profit opportunities which will persist if there is limited arbitrage activity.
