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Posts Tagged ‘perfect capital markets’

Predicting the stock market: it’s normally too late

With worries about Greek exit from the eurozone, with the unlikelihood of further quantitative easing in the USA and the UK, with interest rates likely to rise in the medium term, and with Chinese growth predicted to be more moderate, many market analysts are forecasting that stock markets are likely to fall in the near future. Indeed, markets are already down over the past few weeks. Since late April/early May, the FTSE is down 4.5%; the German DAX index is down 7.0%; the French CAC40 index is down 6.9%; and the US Dow Jones index is down 2.3%. But does this give us an indication of what is likely to happen over the coming months?

If stock markets were perfectly efficient, then all possible information about the future will already have been taken into account and will all be reflected in current share prices. It would be impossible to ‘get ahead of the game’.

It is only if market participants have imperfect information and if you have better information than other people that you can are likely to predict correctly what will happen. Even then, the markets might be buffeted by random and hence unpredictable shocks.

Some people correctly predicted things in the past: such as crashes or booms. But in many cases, this was luck and their subsequent predictions have proved to be wrong. When financial advisers or newspaper columnists give advice, they are often wrong. If they were reliably right, then people would follow their advice and markets would rapidly adjust to their predictions.

If Greece were definitely to exit the euro, if interest rates were definitely to rise in the near future, if it became generally believed that stock markets were overvalued, then stock markets would probably fall. But these things may not happen. After all, people have been predicting a rise in interest rates from their ultra-low levels for many months – and it hasn’t happened yet, and may not happen for some time to come – but it may!

If you want to buy shares, you might just as well buy them at random – or randomly sell any you already have. As Tetlock says, quoted in the Nasdaq article:

“Even the most astute observers will fail to outperform random prediction generators – the functional equivalent of dart-throwing chimps.”

And yet, people do believe that they can predict what is going to happen to stock markets – if not precisely, then at least roughly. Are they deluded, or can looking calmly at likely political and economic events put them one step ahead of other people who perhaps behave more reactively and emotionally?

Bond rout spells disaster for stock markets as global credit kraken awakens The Telegraph, John Ficenec (14/6/15)
Comment: Many imponderables for markets The Scotsman, Bill Jamieson (14/6/15)
How Ignoring Stock Market Forecasts Will make you a better investor Forbes, Ky Trang Ho (6/6/15)
The Predictions Racket Nasdaq, AdviceIQ, Jason Lina (21/5/15)

Questions

  1. Why may a return of rising interest rates lead to a ‘meltdown in equity prices’? Why might it not?
  2. Why have bond yields fallen dramatically since 2008?
  3. Why are bond yields rising again now and what significance might this have (or have had) for equity markets?
  4. Why may following the crowd often lead to buying high and selling low?
  5. Is there an asymmetry between buying and selling behaviour in stock markets?
  6. Will ignoring stock market forecasts make people better investors?
  7. “The stock market prices suggest that investors believe both the Federal Reserve and the Bank of England are bluffing about raising interest rates. That may be so, but it is an extremely risky game of chicken for investors to play.” Explain and discuss.
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