Market Efficiency

Market Efficiency



Market Efficiency

Chapter 18 Market Efficiency

1.       Objectives

1.1       Distinguish between and discuss weak form efficiency, semi-strong form efficiency and strong form efficiency.
1.2       Discuss practical considerations in the valuation of shares and businesses, including:
(a)        Fundamental theory of share values
(b)       Marketability and liquidity of shares
(c)        Availability and sources of information
(d)       Market imperfections and pricing anomalies
1.3       Describe the significance of investor speculation and the explanations of investor decisions offered by behavioural finance.

2.       The Efficient Market Hypothesis


The Efficient Market Hypothesis


This hypothesis states that the stock market reacts immediately to all the information that is available. Thus a long term investor cannot obtain higher than average returns from a well diversified share portfolio.

2.2       Types of efficiency

2.2.1    Operational efficiency – This refers to the cost, speed and reliability of transactions in securities on the exchange. It is desirable that the market carries out its operations at as low a cost as possible, speedily and reliably. This may be promoted by creating as much competition between market makers and brokers as possible so that they earn only normal profits and not excessively high profits.
2.2.2    Allocational efficiency – Society has a scarcity of resources and it is important that we find mechanisms which allocate those resources to where they can be most productive. Those industrial and commercial firms with the greatest potential to use investment funds effectively need a method to channel funds their way. Stock markets help in the process of allocating society’s resources between competing real investments. For example, an efficient market provides vast funds for the growth of the electronics, pharmaceuticals and biotechnology industries but allocates only small amounts for slow-growth industries.
2.2.3    Pricing efficiency – It is the focus of this chapter, and the term efficient market hypothesis applies to this form of efficiency only. In a pricing-efficient market the investor can expect to earn merely a risk-adjusted return from an investment as prices move instantaneously and in an unbiased manner to any news.

2.3       Features of efficient markets

2.3.1    It has been argued that the UK and US stock markets are efficient capital markets, that is, markets in which:
(a)        The prices of securities bought and sold reflect all the relevant information which is available to the buyers and sellers: in other words, share prices change quickly to reflect all new information about future prospects.
(b)        No individual dominates the market.
(c)        Transaction costs of buying and selling are not so high as to discourage trading significantly.
(d)        Investors are rational.
(e)        There are low, or no, costs of acquiring information.

2.4       Impact of efficiency on share prices

2.4.1    If the stock market is efficient, share prices should vary in a rational way.
(a)        If a company makes an investment with a positive NPV, shareholders will get to know about it and the market price of its shares will rise in anticipation of future dividend increases.
(b)        If a company makes a bad investment shareholders will find out and so the price of its shares will fall.
(c)        If interest rate rise, shareholders will want a higher return from their investments, so market prices will fall.

2.5       Forms of market efficiency
(Dec 07, Jun 08, Dec 10)


Three Forms of Efficiency


(a)        Weak form efficiency – Under the weak form hypothesis of market efficiency, share prices reflect all available information about past changes in the share price.

Since new information arrives unexpectedly, changes in share prices should occur in a random fashion. If it is correct, then using technical analysis to study past share price movements will not give anyone an advantage, because the information they use to predict share prices is already reflected in the share price.
(b)        Semi-strong form efficiency – If a stock market displays semi-strong efficiency, current share prices reflect both:
(i)        All relevant information about past price movements and their implications, and
(ii)       All knowledge which is available publicly.

This means that individuals cannot “beat the market” by reading the newspapers or annual reports, since the information contained in these will be reflected in the share price.
(c)        Strong form efficiency – If a stock market displays a strong form of efficiency, share prices reflect all information whether publicly available or not:
(i)        From past price changes
(ii)       From public knowledge or anticipation
(iii)      From specialists’ or experts’ insider knowledge (e.g. investment managers).


Test your understanding 1


What would you believe about the efficiency of the market if you thought you could make money by:
(1)        insider dealing
(2)        analyzing past price movements
(3)        only by pure luck
(4)        analyzing financial statements, directors’ statements, company activities, etc.?

2.6       Implications of efficient market hypothesis for the financial manager
(Dec 07)
2.6.1    If the markets are quite strongly efficient, the main consequence for financial managers will be that they simply need to concentrate on maximizing the NPV of the company’s investments in order to maximize the wealth of shareholders.
2.6.2    Managers need not worry, for example, about the effect on share prices of financial results in the published accounts because investors will make allowances for low profits or dividends in the current year if higher profits or dividends are expected in the future.
2.6.3    If the company is looking to expand, the directors will be wasting their time if they seek as takeover targets companies whose shares are undervalued, since the market will fairly value all companies’ shares.
2.6.4    Only if the market is semi-strongly efficient, and the financial managers possess inside information that would significantly alter the price of the company’s shares if released to the market, could they perhaps gain an advantage. However attempts to take account of this inside information may breach insider dealing laws.
2.6.5    The different characteristics of a semi-strong form and a strong form efficient market thus affect the timing of share price movements, in cases where the relevant information becomes available to the market eventually. The difference between the two forms of market efficiency concerns when the share prices change, not by how much prices eventually change.

3.       The Valuation of Shares

3.1       The fundamental theory of share values

3.1.1    Remember that the share values is based on the theory that the realistic market price of a share can be derived from a valuation of estimated future dividends. The value of a share will be the discounted present value of all future expected dividends on the shares, discounted at the shareholders’ cost of capital.
3.1.2    If the fundamental analysis theory of share values is correct, the price of any share will be predictable, provided that all investors have the same information about a company’s expected future profits and dividends, and a known cost of capital.

3.2       Charting or technical analysis

3.2.1    Chartists or technical analysts attempt to predict share price movements by assuming that past price patterns will be repeated. There is no real theoretical justification for this approach, but it can at times be spectacularly successful. Studies have suggested that the degree of success is greater than could be expected merely from chance.

3.3       Random walk theory

3.3.1    Random walk theory is consistent with the fundamental theory of share values. It accepts that a share should have an intrinsic price dependent on the fortunes of the company and the expectations of investors. One of its underlying assumptions is that all relevant information about a company is available to all potential investors who will act upon the information in a rational manner.
3.3.2    The key feature of random walk theory is that although share prices will have an intrinsic or fundamental value, this value will be altered as new information becomes available, and that the behaviour of investors is such that the actual share price will fluctuate from day to day around the intrinsic value.

3.4       Marketability and liquidity of shares

3.4.1    In financial markets, liquidity is the ease of dealing in the shares, how easily can the shares can be bought and sold without significantly moving the price?
3.4.2    In general, large companies, with hundreds of millions of shares in issue, and high numbers of shares changing hands ever day, have good liquidity. In contrast, small companies with few shares in issue and thin trading volumes, can have very poor liquidity.
3.4.3    The marketability of shares in a private company, particularly a minority shareholding, is generally very limited, a consequence being that the price can be difficult to determine.

3.5       Availability and sources of information

3.5.1    It was stated that an efficient market is one where the prices of securities bought and sold reflect all the relevant information available. Efficiency relates to how quickly and how accurately prices adjust to new information.

3.6       Market imperfections and pricing anomalies (異常)

3.6.1    Various types of anomaly appear to support the views that irrationality often drives the stock market, including the following.
(a)        Seasonal month-of-the-year effects, day-of-the-week effects and also hour-of-the-day effects seem to occur, so that share prices might tend to rise or fall at a particular time of the year, week or day.
(b)       There may be a short-run overreaction to recent events. For example, the stock market crash in 1987 when the market went into a free fall, losing 20% in a few hours.
(c)        Individual shares or shares in small companies may be neglected.

3.7       Behavioural finance

3.7.1    Speculation by investors and market sentiment is a major factor in the behaviour of share prices. Behavioural finance is an alternative view to the efficient market hypothesis. It attempts to explain the market implications of the psychological factors behind investor decisions and suggests that irrational investor behaviour may significantly affect share price movements. These factors may explain why share prices appear sometimes to over-react to past price changes.

Examination Style Questions

Question 1
Distinguish between weak form, semi-strong form and strong form stock market efficiency, and discuss the significance to a listed company if the stock market on which its shares are traded is shown to be semi-strong form efficient.                                                                                                     (8 marks)
(ACCA F9 Financial Management December 2007 Q1(c))



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Market Efficiency


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Market Efficiency



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Market Efficiency