Liquidity in Forex, Part No.2 : Analyzing the Liquidity of Different Pairs

On yesterday's article - which was part No.1 of this post - we talked about the definition of liquidity and the implications of high and low liquidity levels on the forex market. Today we are going to give an in-depth look to liquidity in the forex market, particularly I will talk about recent literature in economics dealing with the evaluation of liquidity on several different currency pairs and what we can conclude and use from this analysis. After reading this article you will have an idea about which are the most liquid and illiquid currency pairs, something which should give you a good idea of what pairs you would want to focus on for the development of mechanical trading strategies.

First of all, it is important to understand that liquidity in forex in simply a pain to research. In order to investigate the liquidity levels of any given market instrument we need to have all transaction information including, type, volume and time. This means that we need access to the "books", the registry where all the transaction information of a given broker is kept. Since there is no central exchange in forex, we cannot get the real liquidity values but if we choose a broker that uses a large array of liquidity providers and we take a look at all their transaction we might be able to draw some general conclusions regarding overall pair liquidity values (at least relative to each other).

The Swiss National bank published a paper a few months ago dealing with the evaluation of liquidity on the FX market (you can access it here). Besides discussing previous literature findings regarding forex liquidity the authors investigated the liquidity levels of several different currency pairs using data from 2007 to 2008. The authors used a daily reversal measurement (explained within the paper) of liquidity in order to get a comparable to number to use between the different currency pairs.
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The study's first findings show us that the EUR/USD and USD/JPY were the most traded instruments during the testing periods while the AUD/USD and USD/CAD had the lowest trading volume. The authors also emphasize on the fact that even though the GBP/USD is an important pair it is very illiquid when compared to the EUR/USD, confirming the findings of previous studies and pointing to the reason why the development of GBP/USD based systems is far more difficult than for the EUR/USD since the lower liquidity makes inefficiencies harder to exploit in a mechanical fashion.

Another interesting conclusion is the high liquidity of the USD/CHF and EUR/CHF during this period which the authors attribute to the safe-heaven status of the frank and the economic crisis during 2007-2008. The study also shows us that liquidity is not constant but changes considerably over time with most currency pairs starting to lose liquidity around August 2007 (carry trade unwinding) rebounding slightly and then resuming the downtrend at the end of this year. This analysis shows that stressful periods in the market are characterized by important drops in liquidity having a very strong relationship with risk sentiment.

Perhaps the most important contribution of this article is the development of ways to measure liquidity and the finding of correlations of FX pairs' liquidity with other financial instruments or markets where liquidity is more easily measured. This in turn would allow investors to watch for drops of liquidity, something that could be especially important to those investors looking to shield themselves from crisis periods (investors involved in carry trades for example).

Of course, for us the most important findings are the relative levels of liquidity of the different pairs and their relative relationship. From the above mentioned study we can see that definitely system development should be focused on the EUR/USD and USD/JPY while longer term strategies aimed at "harder" to trade instruments should be used on pairs like the GBP/USD and the USD/CAD.

If you would like to learn more about system development and how you too can develop systems for these currency pairs with sound trading strategies please consider buying my ebook on automated trading or joining Asirikuy to receive all ebook purchase benefits, weekly updates, check the live accounts I am running with several expert advisors and get in the road towards long term success in the forex market using automated trading systems. I hope you enjoyed the article !