Currencies trading are very difficult.

Currencies trading are very difficult. They are more difficult than stocks and certainly more difficult than interest rates.

You need to learn by looking at price behaviour in the past, but trying to understand what currencies have done even recently is tough. There have been some big moves.

Take the US dollar versus euro rate, for example. It has ranged over the last few years from around 85 to 130. How is it possible that the currencies of the world's two largest economies can change in relative value by over 50%?

These types of currency moves are intriguing.

• The first thing to be aware of, is that you are looking at two economies. With stocks and interest rates, youj basically have only one economy to figure out.
• However, the second and bigger challenge is that currencies are largely driven by market sentiment, and the reason is that there is absolutely no successful benchmark for the pricing of a currency.

1. Purchasing price parity (PPP) is not much use

This theory suggests that currencies should tend towards the level where a collection of goods and services costs the same amount in different countries. PPP would suggest that if they are too expensive in one country, then that country's currency should fall.

The famous McDonald's Big Mac index is sometimes published in the Economist magazine, and it applies this analysis, to the price of the burgers in various countries.

The problem is that in reality PPP does not seem to have much impact on currency level. Perhaps it is for the same reason that people living in tiny but very expensive apartments in Tokyo do not migrate to Sydney or LA and buy a huge house. If they did, perhaps currencies would be easier to evaluate.


2. Market sentiment has the most impact

Since there are no reliable benchmarks, market sentiment is the huge factor that dominates events.

In 2005, the US dollar has been out of favour, despite an improving US economy and rising US dollar interest rates. The market is more worried about the US current account deficit. But is that econmies or fashion? There's the difficulty.


Conclusion

You need not avoid currency trading completely.

There are occasional opportunities such as the big market moves that you have seen in the major currencies during the last few years.

You should only be involved when you have a very firm grip on what's driving the market. That doesn't happen too often for any of us!