Tag: efficient market hypothesis

On several occasions in the past on this site we’ve examined proposals for a Tobin tax: see, for example: A ‘Robin Hood’ tax (Feb 2010), Tobin or not Tobin: the tax proposal that keeps reappearing (Dec 2009) and A Tobin tax – to be or not to be? (Aug 2009). A Tobin tax is a tax on trading in financial products, sometimes known as a ‘financial transactions tax’ (FTT). It could also be levied on trading in foreign currencies. It is considered in Economics (7th ed) (section 26.3) and Economics for Business (5th ed) (section 32.4).

The tax would be levied at a very low rate: somewhere between 0.01% and 0.5% and would be too small to affect trading in shares or other financial products for purposes of long-term investment. It would, however, dampen speculative trades that take advantage of tiny potential gains from very short-term price movements. Such trades account for huge financial flows between financial institutions around the world and tend to make markets more volatile. The short-term dealers are known as high-frequency traders (HFTs) and their activities now account for the majority of trading on exchanges. Most of these trades are by computers programmed to seek out minute gains and respond in milliseconds. And whilst they add to short-term liquidity for much of the time, this liquidity can suddenly dry up if HFTs become pessimistic.

The President of the European Commission, José Manuel Barroso, has announced that the Commission has adopted the idea of a financial transactions tax with the backing of Germany, France and other eurozone countries. This Tobin tax could be in operation by 2014. According to the Commission, it could raise some €57bn a year. Unlike earlier proposals for a Tobin tax (sometimes called the ‘Robin Hood tax’), the money raised would probably be used to reduce EU deficits, rather than being given in aid to developing countries.

The UK government has been highly critical of the proposal, arguing that, unless adopted world-wide, it would divert trade away from the City of London.

The following articles consider how such a tax would work and its potential advantages and disadvantages.

Theory inches ever closer to practice Guardian, Larry Elliott (28/9/11)
Osborne expected to oppose EU’s proposal for Tobin tax on banks Guardian, Jill Treanor (28/9/11)
Tobin tax could ‘destroy’ business models Accountancy Age, Jaimie Kaffash (30/9/11)
Tobin tax is likely, says banking chief Accountancy Age, Jaimie Kaffash (5/10/11)
Could a transactions tax be good for capitalism? BBC News, Robert Peston (3/10/11)
EU to propose tax on financial transactions BusinessDay (South Africa), Mariam Isa (5/10/11)
European politicians plot to block UK veto on ‘Tobin tax’ The Telegraph, Louise Armitstead (3/10/11)
Opinion Divided on EU Transaction Tax Tax-News, Ulrika Lomas (5/10/11)
Tobin taxes and audit reform: the blizzard from Brussels The Economist (1/10/11)


  1. What are HFTs and what impact do they have on the stability and liquidity of markets?
  2. Explain how a Tobin tax would work.
  3. What would be the potential advantages and disadvantages of the Tobin tax as proposed by the European Commission (the ‘financial transactions tax’)?
  4. Are financial markets efficient? Can a market be ‘excessively efficient’?
  5. How are ‘execute or cancel’ orders used by HFTs?
  6. Why do HFTs have an asymmetric information advantage?
  7. How does a financial transactions tax differ from the UK’s stamp duty reserve tax?
  8. Explain why the design of the stamp duty tax has prevented the flight of capital and trading from London. Could a Tobin tax be designed in such a way?

From October 2007 to March 2009, stock markets around the world fell massively. In the UK, the FTSE 100 fell from a peak of 6752 on 15 October 2007 to a trough of 3461 on 9 March 2009 (a fall of 49 per cent). By the end of August 2009 it had reached 4944 (a rise since March of 43 per cent). Does this mean that the March value represented an over-correction downwards? Did the subsequent rise represent an over-correction upwards? Are stock markets about to plummet? The following two articles reflect on the past and look into the future!

World Wide Stock Market Crash on Pause The Market Oracle (3/9/09)
Are shares about to fall off a cliff? BBC News (4/9/09)


  1. What is meant by the ‘efficient (capital) market hypothesis’?
  2. If stock markets are overvalued, does this mean that they are inefficient?
  3. Why might (a) stock markets plummet in the near future; (b) carry on rising? Why don’t the ‘experts’ know which will happen?
  4. Explain why markets may over-shoot their long-term equilibrium value?

Both business and consumer confidence are affected by the state of the economy. A recession, or even a slowdown in the economy, will make people worried for their jobs and future incomes and hence cut back on spending and either save more or reduce their debts. Similarly firms are likely to cut back on investment if they are pessimistic about the future. But both consumer demand and investment are components of aggregate demand. A cut in aggregate demand will drive the economy further into recession and cause even greater pessimism. In other words, there is a feedback loop. Recession causes pessimism and hence a fall in aggregate demand, which, in turn, worsens the recession.

A similar process of feedback occurs in times of optimism. If the economy recovers, or is thought to be about to do so, the resulting optimism will cause people and firms to spend more. This rise in aggregate demand will help the process of recovery (see Accelerating the recession and Animal Spirits).

The following article by Robert Shiller, co-author of Animal Spirits: How Human Psychology Drives the Economy, and Why It Matters for Global Capitalism, looks at the swing from pessimism to optimism over the past few months.

An Echo Chamber of Boom and Bust: Robert Schiller New York Times (29/8/09)
Efficient Market Hypothesis: True “Villain” of the Financial Crisis? The Market Oracle (26/8/09)

Monthly confidence indicators for the EU can be found at:
Business and Consumer Surveys: Time Series European Commission Directorate-General for Economic and Financial Affairs. (Each of the ‘en’ cells links to a zipped Excel file.)


  1. Explain why “confidence has rebounded so quickly in so many places” in recent weeks.
  2. Is Robert Shiller’s explanation of feedback loops consistent with the accelerator theory?
  3. In what circumstances do business and consumer psychology result in destabilising speculation and what causes turning points in the process? Why may such turning points be difficult to predict?
  4. Examine the monthly Economic Sentiment Indicator (ESI) for the UK from the ‘Business and Consumer Surveys: Time Series’ link above. You will need to refer to the final column in the Excel ESI Monthly worksheet (Column GV). Chart the movements in this indicator over the past three years. Also chart the quarterly growth in UK GDP over the same time period. You can find data from Economic and Labour Market Review (ONS), Data tables, Table 1.01, Column YBEZ. Is ESI a leading or a lagging indicator of GDP?
  5. What implications does Shiller’s analysis have for the management of the economy?
  6. Why may stock market movements not be a ‘random walk’?

Whilst some economists predicted the banking crisis of 2007/8 and the subsequent global recession, many did not. Was this a failure of macroeconomics, or at least of certain macroeconomic schools of thought, such as New Classical economics? Or was it a failure to apply the subject with sufficient wisdom? Should the subject be radically rethought, or can it simply be amended to take into account aspects of behavioural economics and a better understanding of systemic risk?

The four linked articles below from The Economist look at the debate and at the whole state of macroeconomics. The other articles pick up some of the issues.

Will the ‘crisis in macroeconomics’ lead to a stronger subject, more able to explain economies in crisis and not just when they are working well? Will a new consensus emerge or will economists remain divided, not only about the correct analysis of how economies work at a macro level, but also about how to tackle crises such as the present recession?

What went wrong with economics The Economist (16/7/09)
The other-worldly philosophers The Economist (16/7/09)
Efficiency and beyond The Economist (16/7/09)
In defence of the dismal science The Economist (6/8/09)
How to rebuild a shamed subject Financial Times (5/8/09)
What is the point of economists? Financial Times – Arena (28/7/09)
Macroeconomic Models Wall Street Pit (23/7/09)
Macroeconomics: Economics is in crisis – it is time for a profound revamp Business Day (27/7/09)


  1. Distinguish between ‘freshwater’, ‘saltwater’ and ‘brackish’ macroeconomics.
  2. Explain why economists differ over the efficacy of fiscal policy in times of recession. To what extent does the debate hinge on the size of the multiplier?
  3. Why is the potential for macroeconomics higher now than prior to the recession?
  4. What is meant by the ‘efficient market hypothesis’? How did inefficiencies in financial markets contribute to the banking crisis and recession?
  5. Should economists predict the future, or should they confine themselves to explaining the present and past?