The secret to the rule is that there is no secret. It’s really very simple. Avoid stocks on the long side trading below their 200-day moving average, period. It’s a mathematical fact that a stock needs to first deteriorate below its average 200-day price before running into significant trouble. Generally, stocks don’t implode from new highs overnight, rather, there tends to be a gradual deterioration that starts to accelerate. For example, business conditions may begin to decline, which affects earnings and profitability, which in turn triggers insider and astute analysts selling the stock. As the difficulties mount, financial reporting trickery may develop to boost perceived performance. Eventually, the truth washes out and markets respond accordingly with massive selling. The 200-day moving average is highly effective (I quantified it in the post linked above) because it tends to trigger in the early part of the move, or when insiders and astute analysts start to sell. Have a look at the chart below for Steinhoff. We removed the stock from our tradeable universe in September last year. As a result, not one of our clients were exposed to the stock.

Here’s another example in ABIL. The reasons for failure are different, but the price behaviour is always the same, and price never lies. The landscape is littered with such examples and the evidence is clear, this simple technique really works. In fact, had you employed it, you would have outsmarted literally the entire professional asset management space in South Africa, that are now reeling from the losses. So next time you se a stock dip below it’s 200-day moving average, remember, the downside risks have risen considerably.

]]>In this post, I’ll explore the performance profile of mean reversion, examine tail risk and share some methods that can be used to mitigate tail risk. Interestingly, the common approaches to controlling risk, such as the use of stop losses, actually make matters worse. I’ll share alternatives that prove more effective.

Before we discuss methods to mitigate the tail risk inherent in mean reversion, lets first take a look at the performance profile of a simple mean reversion strategy and discuss what is meant by tail risk. The return distribution below is from a long only mean reversion strategy that enters stocks on short-term weakness and exits on short-term strength. It does not use stop losses. We’ll examine the use of stops next, for now, I want to focus on the trade return distribution, which is typical of mean reversion.

Examining the return distribution below, it’s clear that short-term mean reversion strategies enjoy high winning rates – the green bars represent positive returns, and make up the majority of the distribution – but small average returns– the most frequent return is captured by the tallest green bar which represents returns between +2% and +3%. This combination of high winning rates and small returns is what feeds the compounding machine and which leads to relatively low volatility and consistent performance. This is a very desirable attribute which resulted in my researching and trading this approach for the last decade.

There is however a dark side to mean reversion (isn’t there always; trading is about compromise) which is associated with the distribution’s strong negative skew in the left tail. This is represented by the greater number of more extreme negative returns relative to the positive returns. For instance, the best performing trade generated +14%, while the worst performing trade resulted in a -23% loss. Moreover, there are 21 positive returns above +10%, but 78 negative returns less than -10%! This is the nasty negative skew in the left tail of mean reversion. For every return greater than +10%, there are 4 negative returns that exceed -10%. These extreme left tail losses can result in significant portfolio damage if not controlled for properly. So how do we manage the risk associated with the left tail? What about stop losses?

An obvious starting point to control risk is the use of a stop loss. This seems intuitive since we’re looking to contain extreme losses, but as is often the case in trading, what seems logical does not always work. This is one of those instances. In fact, stop losses make matters far worse, often halving returns and doubling drawdown. Below are the return distributions when implementing a 5% and 10% stop loss respectively.

The distributions clearly show the problem when stops are applied to mean reversion – they lock in the loss of multiple trades that would have otherwise resulted in positive returns or smaller losses if closed with the original exit strategy, which waited for the trade to start its reversion. I’ve run this analysis to include a stop loss as far as 50% away from the entry point, and incredibly performance still deteriorates relative to no stops, albeit marginally. Basically, stop losses are not an effective way to control left tail losses because they tend to be triggered by extreme intraday moves driven by emotion that have a high propensity to reverse. All a stop loss does is guarantee the loss without the ability to participate in the likely recovery. That said, a stop loss may be useful when used in the context of a catastrophic loss. This can be achieved by setting the stop far enough away from price so as not to erode performance, but close enough to prevent catastrophic losses. In our case, 50% would work well.

If stop losses don’t work, how do we control for tail risk in mean reversion? Let’s examine a couple of techniques that have proven to be effective.

Set your trade size at a level that would not result in material losses if the worst hypothetical trade return were exceeded by a factor of two or three. The strategy discussed above experienced a worse loss of -23%, so by this measure we should allow for losses in our trading of around -50%. With this figure in hand, we can now set a position size that ensures we remain within our loss tolerance band. For instance, if we intend to restrict our worst losses to no more than -10% of equity, then we would allow ourselves a position size of 20% of equity (on a R100K account, that would amount to a R20K position, which would result in a R10K loss, or -10%, if the trade fell -50%). However, keep in mind that multiple extreme losses could occur together, which we need to make provision for.

Set limits for the strategy in terms of the amount of exposure that it’s allowed to assume in a single sector. Market moving news tends to effect sectors in their entirety so allowing a strategy to expose itself 100% to a given sector will amplify the effects of the left tail when the sector experiences material game changing events.

Markets tend to see very high levels of correlation in the short-term during significant broad market moves, especially when driven by fear to the downside. Therefore, allowing a strategy to gain 100% of its exposure in a single day increases mean reversion’s left tail risk as the strategy is sucked into multiple correlated positions on the same day. It’s far more effective to restrict a strategy’s allocation on any one day to a percentage of equity.

This is something our professional platform, QuantLab, does exceptionally well. Instead of allocating capital to a single entry or exit point in each trade, rather look to divide the capital into portions and allocate to different entry and exit points. We will never capture the perfect bottom and top consistently through time, so why allocate capital in such a manner? By spreading capital across multiple entry and exit points, we capture the average trade through time. This has some incredibly powerful performance attributes, not least of which is it helps reduce the impact of tail risk.

Diversify in every possible way to reduce equity exposure to any one idea. Include many mean reversion strategies in many different global markets. Include different non-correlated strategies, like for instance trend following strategies. The idea here is to have as many small positions as possible spread across as many ideas as possible. When you reach this level of diversification, position sizes are so small relative to total equity that even if a trade moves 100% against your portfolio the losses are so small to be almost insignificant.

Employing some or all of these techniques will help to reduce the effects of the nasty left tail inherent in mean reversion. Taken to the extreme, when implementing all the methods discussed, the risk of the left tail is essentially eliminated, or at the very least, significantly reduced. What is however clear is the ineffectiveness of stop losses in short-term mean reversion strategies.

Happy Trading,

PJ

In the Podcast I discuss mean reversion in detail as well as some of the powerful ideas that we use within our platforms. If you’re looking to gain a better understanding of our approach, or simply to broaden your trading knowledge, then this Podcast is well worth listening to. Hope you enjoy, and if you have any questions I’d be happy to answer them.

http://bettersystemtrader.com/062-mean-reversion-strategies-pj-sutherland/

]]>Over the years I’ve tested and analysed the performance of countless trading strategies. Through the process I’ve learned that the performance profile of any strategy falls within either of the following:

- Moderate to high activity, high win rates, low average gains and consequently low risk/reward ratios and fat left tails.
- Low activity, low win rates, high average returns and consequently high risk/reward ratios and fat right tails.

The first profile is typical of mean reversions strategies, while the second trend following strategies. It doesn’t matter whether you’re employing fundamental, technical, economic or any of form of data to drive the decision making, the performance profile will resemble one of the above. This essentially has to do with the way trades are closed – if the exit strategy capitalises on long pronounced trends, then you’re going to see a performance profile that resembles that of trend following. On the other hand, if a strategy seeks to lock in small and frequent gains, the performance profile will more closely resemble that of mean reversion.

The stark differences in performance statistics across each of these approaches leads to a unique set of risks, which in turn provide some insight into the suitability of each approach with a given set of markets. Next we’ll explore these risks and then look for markets that are more conducive to reducing these risks, providing each approach with the best set of market conditions for success.

Mean reversion strategies do not let profits run since the target exit point is the mean. Essentially, they cut profits short which results in many small gains but infrequent and large losses – make small gains every month and then loose a fortune in a single month. Therefore, the single most significant risk to mean reversion lies in the left tail, or the probability that the market will trend severely against us (price shocks).

Trend following strategies let profits run, but since trends are rare, they experience many small losses and few large gains. Although losses are small, their frequency can result in large overall losses to a portfolio. Therefore, the primary risk to trend following is the cumulative effect of many consecutive losses, or said differently, the market’s inability to trend.

We can then conclude that mean reversion is better suited to markets that are less susceptible to powerful trends, while trend following is better suited to markets that tend to display powerful trends. As a result, we tend to find that either mean reversion or trend following work at any given moment, but not at the same time, that is, they’re mutually exclusive.

I’m now specifically examining the equity markets. Let’s see if we can uncover segments of the market that are better suited to each approach.

Which market segment is more prone to trend? What about large cap stocks? Well, for one thing these stocks are broadly followed, have already disrupted their respective markets and are well established. Therefore, the ability of large cap stocks to continually deliver products or services with massive market impact deteriorates, reducing the probability of significant future price trends.

What about small cap and mid cap stocks? These companies are still in the process of establishing themselves, are not as broadly followed and may provide technologies or services with the potential to significantly disrupt markets resulting in massive growth and powerful price trends.

The above premises are intuitive and make economic sense. Moreover, they bear themselves out in the data. I’ve quantified this extensively and found this to universally hold, not matter which exchange from the global markets we consider. With this knowledge we can now assign the most suitable approach to each market segment thereby boosting our chances of success.

Trend following strategies are far more effective in the mid cap and small cap market segment (long only – shorting the equity market to capture trends is exceedingly difficult due to the strong upward bias that equities display). These market segments provide the best hope of capturing extended price trends that can easily offset the many small losses that result from high losing rates and are consequently perfectly suited to trend following.

On the other hand, mean reversion strategies work much better on large cap stocks. These stocks have reduced price shock risk and their strong following means professionals actively support stocks during sell-offs (institutions love buying dips) and often engage in profit taking during short-term bursts to the upside, which results in precisely the behaviour we’re after for successful mean reversion.

Trends take time to mature, which is why trend following approaches are better suited to longer time frames or longer holds. In fact, using weekly or monthly data yields better results than daily data. Because mean reversion is actively seeking to avoid long powerful trends, they tend to work better in shorter time frames. Therefore, daily data is more appropriate, and unless you have access to fundamental data that you can use as an overlay to gauge the health of a stock, mean reversion does not work well on weekly or monthly data because price is given too much room to mature into a powerful trend against us.

The unique performance characteristics of mean reversion and trend following make them ideal complements within a single portfolio. Mean reversion works well to bring some consistency to a portfolio, while trend following keeps the door open for the rare but significant right tail trends that can lead to fantastic outsized returns. Blending the two approaches in a single portfolio yields very desirable trade return distributions that enjoy both higher win rates and right skew. As a result, it’s my view that a blended approach is as close to holy grail as we can get. And the exciting news is that you can expect to see a multitude of powerful trend following strategies added to QuantLab within the next twelve months. Including trend following in our diverse offering will greatly improve our diversification abilities and further empower clients to build truly powerful and robust portfolios that enjoy exceptional trade return distributions.

Happy Trading,

PJ

A well-known and often quoted measure of risk is the Sharpe ratio. Developed in 1966 by Stanford Finance Professor William F. Sharpe, it measures the desirability of an investment by dividing the average period return in excess of the risk-free rate by the standard deviation of the return generating process. In simple terms, it provides us with the number of additional units of return above the risk-free rate achieved for each additional unit of risk (as measured by volatility). This characteristic makes the Sharpe ratio an easy and commonly used statistic to measure the skill of a manager and can be interpreted as follows: SR >1 = lots of skill, SR 0.5-1= skilled, SR 0-0.5 = low skilled, SR = 0 = no skill and conversely for negative numbers. Although the Sharpe ratio can be an effective means of analysing investment performance, it has several shortcomings that one needs to be aware of and which I’ll discuss below. But before I do, here is the formula for calculating the Sharpe ratio:

**(Mean Portfolio Return – Risk-Free Rate) / Standard Deviation of Portfolio Return**

The most obvious and glaring flaw is the fact that the Sharpe ratio does not differentiate between upside (good) and downside (bad) volatility. Thus, a performance stream that experiences more positive outliers (a good thing for investors) will simultaneously experience elevated levels of volatility which will decrease the Sharpe ratio. This means that one can improve the Sharpe ratio for strategies that exhibit a positive skew in their return distribution (many small losses with large infrequent gains), for instance trend following strategies, by simply removing some of the positive returns, which is nonsensical because investors generally welcome large positive returns.

On the flipside, strategies with a negative skew in their return distribution (many small gains with large infrequent losses), for instance option selling strategies, are much riskier than the Sharpe ratio would have us believe. They often exhibit very high Sharpe ratios while they are “working” because they tend to produce consistent small returns that are punctuated by rare but painful negative returns.

The reason for the shortcomings discussed above can be attributed to the fact that the Sharpe ratio assumes a normal distribution in returns. Although strategy and market returns can resemble that of a normal distribution, they generally are not; if they were then we would expect some of the market moves we’ve experienced within the last decade to occur once in a blue moon, but they evidently do not. This is the result of the phenomena referred to as “fat tails”, or the market’s higher probability of realising more extreme returns than one would expect from a normal distribution. This, in and of itself, is reason enough to be dubious of blindly evaluating a manager or strategy’s performance based on a Sharpe ratio without an understanding of exactly how the returns are made.

One also needs to place the reason for the Sharpe ratio’s initial development into perspective. It was conceived as a measure for comparing mutual funds, not as a comprehensive risk/reward measure. Mutual funds are a very specific type of investment vehicle that represent an unleveraged investment in a portfolio of stocks. Thus, a comparison of mutual funds in the 60’s, when the Sharpe ratio was developed, was one between investments in the same markets and with the same basic investment style. Moreover, mutual funds at the time held long-term positions in a portfolio of stocks. They did not have a significant timing or trading component and differed from each other only in their portfolio selection and diversification strategies. The Sharpe ratio therefore was an effective measure to compare mutual funds when it was first developed. It is however not a sufficient measure for comparing alternative investments such as many hedge funds because they differ from unleveraged portfolios in material ways. For one thing, many hedge funds employ short-term trading strategies and leverage to enhance returns, which means when things go wrong money can be lost at a far greater rate. Moreover, they often do not provide the same level of internal diversification nor have lengthy track records.

Investors that do not understand the difference between long-term buy-and-hold investing and trading, often incorrectly measure risk as smoothness in returns with the Sharpe ratio. Smoothness does not equal risk. In fact, there is often an inverse relationship between smoothness and risk – very risky investments can offer smooth returns for a limited period. One need only consider the implosion of Long-Term Capital Management which provided very smooth and consistent returns (excellent Sharpe ratio) before being caught in the Russian default on bonds which created a financial crisis.

The strategies that we employ in QuantLab would be categorised as alternative in nature and do not mimic typical mutual funds. Therefore, the Sharpe ratio is not the most suitable measure to assess our performance. So, let’s examine a couple of alternatives to the Sharpe ratio.

The Sortino ratio is like the Sharpe ratio but differs in that it takes account of the downside deviation of the investment as opposed to the standard deviation – i.e., only those returns falling below a specific target, for instance a benchmark. Formula:

**(Mean Portfolio Return – Risk-Free Rate) / Standard Deviation of Negative Portfolio Returns**

The Sortino ratio in effect removes the Sharpe ratio’s penalty on positive returns and focuses instead on the risk that concerns investors the most, which is volatility associated with negative returns. It is interesting to note that even Nobel laureate Harry Markowitz, when he developed Modern Portfolio Theory (MPT) in 1959, recognized that because only downside deviation is relevant to investors, using it to measure risk would be more appropriate than using standard deviation.

We can see the effects of removing the penalty on positive outliers with the Sortino ratio by examining our live performance in QuantLab, which to date exhibits a strong positive skew – we’ve enjoyed several large positive outliers – so the Sharpe ratio unfairly penalises our performance. In fact, if we remove the effect of positive volatility (good for investors), QuantLab’s risk-adjusted performance improves from 1.11 (Sharpe) to 1.85 (Sortino). However, since the return stream of QuantLab is asymmetric, that is it displays skew and is not symmetric around the mean, the standard deviation is not an adequate risk measure (as discussed above). Although the Sortino ratio improves on the Sharpe ratio for performance profiles that exhibit positive skew, it still suffers from the flawed assumption that returns are normally distributed, which is required when using the standard deviation to measure risk.

There is however an alternative risk/reward measure free of the shortcomings discussed above which I personally prefer to use when evaluating performance. I’ll explore this measure next.

In an absolute sense, the most critical risk measure from an investors perspective is maximum drawdown because it measures the worst losing run during a strategy’s performance. A pragmatic approach then to measuring risk/reward is to determine how well we’re compensated for assuming the risk associated with drawdown. This is precisely what the MAR ratio achieves. It was developed by Managed Accounts Reports (LLC), which aptly reports on the performance of hedge funds. The ratio is simply the compounded return divided by the maximum drawdown. Provided we have a large enough sample, the MAR ratio is a quick and easy to use direct measure of risk/reward; It tells you how well you’re being compensated for having to risk your capital though the worst losses. The formula follows:

**CAGR / Max DD**

l find this ratio immensely useful. It’s simple, does not rely on flawed assumptions about market return distributions such as standard deviation, which is used in both the Sharpe and Sortino ratios, and it measures what’s important to investors: the number of units of return delivered for every unit of direct risk (maximum drawdown) assumed. When we use this metric to measure our live performance to date we find that QuantLab has delievered three units of return for every unit of risk, that is, our live MAR ratio is currently 3.

The MAR ratio is a transparent and direct measure of risk and reward that is impossible to manipulate (the Sharpe and Sortino ratios can be manipulated higher in several devious ways) and is thus my preferred measure of risk-adjusted performance when evaluating strategies.

We all have unique return expectations and tolerance for pain. For this reason, there is no single measure that appeals universally to everyone. In my personal trading, I analyse the MAR ratio, maximum drawdown, overall return and like to keep an eye on the smoothness in which returns are generated by examining the Coefficient of Variation, Sharpe and Sortino ratios. Keep in mind that regardless of the statistic you use, they are good estimates at best. Therefore, one can never be too conservative when analysing past performance. Given a long enough timeline, every strategy will exceed its maximum drawdown. This is a harsh reality that we as traders need to accept and prepare for, so it’s a good idea to be suspicious of any statistic and ensure we have buffers built into our expectations to handle new extremes that will likely be posted in the future.

As always, I welcome your thoughts and suggestions.

Happy Trading,

PJ

A blog series to contrast the key distinctions between trend following and countertrend strategies during building, testing and trading. In this post we examine the effects of data integrity and simulated trade sample size on backtested performance.

One of the major obstacles for traders looking to research trend following models is data. Since trend following models look to “cut losses short and let winners run”, profitable trades can last for many months or even years. This inherent characteristic has two important implications. First, it results in much longer trade duration’s and consequently fewer simulated trades from a backtest. Second, due to the strong positive skew in trade returns, a small number of highly rewarding trades contribute to the majority of the overall return. These characteristics combined mean that trend following strategies are very sensitive to potential data biases – they cannot tolerate data that has not been fully and properly adjusted for corporate actions and survivorship bias. “Garbage in, garbage out” aptly describes the effect of poor quality data on the backtesting process with respect to trend following. And you’re out of luck if you think that you can simulate the effects of perceived data biases – the concentration of overall return, relatively low number of simulated trades and material impact of survivorship bias makes it near impossible to estimate the effects of known data shortcomings when employing poor quality data for trend following backtesting.

Unfortunately, few retail offerings provide the rigour needed to ensure properly adjusted price datasets. It’s however possible to acquire data that has been professionally prepared for commercial entities in the asset management space, but these are costly and generally out of reach to the private investor.

Successful countertrend strategies on the other-hand are more short-term in nature, with trades lasting days as opposed to months. The shorter holds result in much higher number of simulated trades from a backtest. Another important distinction is that countertrend strategies have relatively low risk/reward ratios but high win rates, so their performance is not dependent on a few highly rewarding outcomes, but rather many small gains. These attributes – large number of historical trades with short duration’s and low past trade return concentration – make countertrend strategies less sensitive to data integrity issues. One additional upside associated with the low trade return concentration (many trades contribute to the overall strategy return, as opposed to few trades as with trend following) is the ability to simulate some of the likely effects of the known data integrity issues on performance. For instance, we could remove the top 10% of most profitable trades from our simulated database to allow for survivorship bias and corporate actions and then rerun the test to determine the effect on overall performance. Essentially, we can emulate a test done on high quality data by massaging the performance numbers downward to allow for perceived data integrity issues.

Many retail offerings provide cheap end-of-day equity price data that are “good enough” to test countertrend strategies. For most retail traders, countertrend strategies are better suited to the data solutions currently available. If you do not have the budget nor understand the intricacies involved in testing long-term strategies, then short-term strategies, such as a countertrend approach, is likely a better place to start.

As discussed above, countertrend strategies generate a much larger number of simulated trades during a backtest relative to trend following strategies. This is one of the most desirable aspects of a short-term approach because sample size is the single most significant contributor to our confidence in estimating the future – the more simulated trades we have, the higher our confidence in future performance. Smaller samples are more susceptible to the effects of good or bad luck during a backtest, which can over or underestimate the underlying edge that a strategy exploits. Consequently, the expected performance in any given year for a trend following strategy is far less certain relative to a countertrend strategy – our confidence bands are set wider as a direct result of a smaller number of historical trades.

After data integrity, trade sample size from a backtest is the most effective metric to gauge the robustness of a strategy, and oddly enough the least spoken about in trading circles. Sample size is so powerful that it doesn’t matter whether or not we understand why a given strategy works – as the trade sample increases, the probability that the strategy works due to chance alone decreases, and ultimately approaches zero. This fact alone is reason enough for most private investors to abandon research on long-term approaches and instead focus on short-term approaches.

Countertrend strategies, or short-term strategies in general, are much more forgiving when it comes to price data integrity issues. Regardless of whether you have high quality data or not, countertrend strategies always provide for higher levels of confidence in future performance due to the greater number of simulated trades relative to their trend following counterparts. For these reasons, most private investors will be better served by focusing their energies on developing short-term trading strategies as opposed to long-term strategies.

In my next post I’ll explore and discuss the most appropriate markets for each approach. As always, I welcome your thoughts and suggestions.

Happy Trading,

PJ

Following on from my previous post, in which I discussed a similar short-term diffusion approach, I’m going to share the performance of another simple breadth indicator this week. This study serves to confirm that breadth is a valuable addition to any trader’s toolkit. QuantTrade – our new product set to launch any day now – will provide traders with free access to a broad spectrum of quantified breadth indicators that they can use to enhance the quality of their trade signals. All the breadth indicators discussed in my blog will be included in our free offering so be sure to lookout for that. I know of vendors in South Africa that charge a fare penny for this data, so we’re excited to be in a position to give back to the trading community.

This week’s indicator is simply the percentage of liquid stocks trading on the JSE that have closed lower than their closing price the day before. Because we know that equities exhibit a strong propensity to revert to the mean after moving strongly in one direction, we expect to see the JSE Top 40 Index move in the opposite direction following high readings in our breadth indicator. For instance, if more than 80% of equites close lower today, then the theory of mean reversion states that the market should favour a rise in price during the next trading session. Let’s see if our theory holds up?

To test this theory I applied our breadth indicator to the Satrix 40, which is a tradeable ETF (Exchange Traded Fund) listed on the JSE, since its inception in 2000. The Satrix 40 tracks the JSE Top 40 Index and can be readily traded just like any other stock listed on the exchange.

Here are the rules that I used:

Entry: Today more than 80% of liquid listed JSE equities closed lower than their close yesterday

Exit: Exit the following day after an entry at the closing price

Since 2000 this simple breadth indicator predicted a rise in price with 60% accuracy following our trade signal. That’s an impressive track record given the simplicity of our indicator. Traders definitely want to pay attention to these readings, at least in the short-term.

*Are you looking for a calculated approach to trading that relies on statistics as opposed to human opinion and gut feel?*

*Do you have R15 000 to fund a trading account?*

*If you answered yes to the above then be sure to trial our new product for free on 1 August 2015!*

*Key Features:*

*• Big picture analysis giving you access to quantified metrics across 37 exchanges*

*• JSE market breadth analysis providing a quantified look at the JSE internal strength*

*• 1 million quantified strategy variations – remove guesswork from your trading!*

*• Powerful quantified short-term stock rating system*

*• PJ’s daily battle plan where I’ll discuss how and why I’m using each quantified strategy daily*

*• Extremely powerful performance monitoring system synced precisely to your broker’s account*

You probably will not want to trade this indicator on its own, however, by overlaying this as a trade filter in one of your strategies you will likely see a boost in win rates and average trade returns.This is exactly what I aim to do in our new product, and the quantified results are impressive. In fact, market breadth will form an integral part of my daily analysis in my Daily Battle Plan. I’ll use breadth daily to set risk management, directional bias and strategy selection. If you aren’t already using breadth as an input into your trading then I suggest you begin exploring the concept further.

And if these results don’t impress you, remember that Las Vegas was built on 52% favourable odds. Trading is all about tilting the table ever so slightly in your favour and then managing risk. This little indicator does a superb job of placing the odds on our side.

As always, I welcome your comments. Until next week, happy trading.

Happy Trading,

PJ

I have the privilege of working with two of the sharpest minds in the industry. Last week I had a discussion with them via email about selecting a suitable benchmark for the strategies I run. I was specifically questioning them on the use of cash returns as a benchmark. This is a contentious issue in the industry – many folk disagree with cash as a benchmark because they don’t understand the reasons for its use. I found the answers to my questions clear and concise, providing easy to understand insights into cash as a benchmark. The discussion has implications for QuantLab that runs the same strategies referred to in the discussion. QuantLab is currently benchmarked against the JSE Top 40, but theoretically it should be benchmarked against cash returns, or government treasury bills. Another useful benchmark, to determine relative skill, would be an appropriate hedge fund index. Neither of these – treasury bills nor hedge fund index – are currently used in QuantLab to benchmark performance. In light of this, I will look to add both of these at some future point. I thought that you’d find the discussion interesting so I’ve included it in today’s post.

**PJ: I know that we currently use cash returns to benchmark performance, but I don’t agree that adequately reflects the risk in the fund. Cash basically has zero volatility, which is not the case with our fund. I guess we need to find a benchmark with the same generic risk drivers. Not sure what this is though?**

Director: Cash is the official benchmark and – because we do not hold any systematic, long-term exposure to any risk asset/class – is also theoretically the correct answer even if there is a difference in volatility. A benchmark does not need to exhibit the same vol characteristics in order to be valid; small cap equities for example would have much higher volatility than large cap yet both can accurately be benchmarked against an all-share index. In fact, volatility relative to the benchmark (akin to beta in the mean-variance world) becomes one of the key risk statistics that an investor should be concerned with.

The next best comparator would be to recognise we are an “active trading strategy” and therefore the benchmark would be “other active trading strategies” or the “universe of active trading strategies”, which is proxied by one or more hedge fund indices, covering either the entire HF universe or more granular ones like stat arb or LS equity.

Given there is no neat answer like there would be for an active equity fund, we show our performance against most of the above in our materials, including things like the Sharpe Ratio (which captures risk-adjusted returns against cash).

**PJ: Thanks for the insights. How do we display skill or “alpha” – residual returns over and above our risk budget – when benchmarked against a risk-free portfolio? A comparative HF index appears more sensible?**

Director: In order to determine skill in an absolute sense, your starting point needs to be the portfolio you would hold if you have no views at all.

In our case, that is 100% cash.

For other strategies, the starting point could be an equity index or a bond index if that is what would be held if the manager had no active views.

Skill is then displayed by examining how many units of return are added per unit of additional risk (generally [active] volatility). i.e. typically a Sharpe Ratio or an Information Ratio.

The fact that your starting point is a risk-free, zero-volatility point is not important. Mathematically the demonstration of skill would be the same regardless of the benchmark.*

If you benchmark yourself against a HF index, you determine relative skill; that is, whether you have more or less skill than others trying to do the same thing. That only becomes relevant once we have determined you have some skill in the first place, and in that case the client would correctly be asking how does your skill compare with the skill of others.

– Are you a high-skill or a low-skill operator? For this we would look at e.g. typical observed thresholds for Sharpe Ratios, being something like SR > 1.0 = lots of skill, SR 0.5-1.0 = skilled, SR 0.0-0.5 = low skill, SR = 0.0 = no skill and conversely for negative numbers.

– Are your results visibly better or worse than your peer group, if there is one? This can be answered by looking at e.g. comparative equity fund performance risk-adjusted return or Sharpe Ratio ranking, bond performance ranking, HF index etc depending on the strategy in question.

Beyond that there are many other questions related to skill such as:

– Is there enough skill to cover any costs, fees, expenses or other slippage? We show net returns so presumably that answers itself.

– Is your strategy unique or are there other barriers to investment for me to the point where any skill you may have – even low skill – is worth having because it diversifies my total portfolio in a meaningful way? For example you may be the only operator with an appropriate fund structure so I might invest with you even if you have below average skill.

– Has the skill been commoditised? That is, could I get the same result in an easy-to-obtain, replicated fashion, say through an ETF which executes the same strategy in a less person-dependent or human-error-prone way? Could be very relevant for e.g. a long-only small-cap strategy where well-defined ETFs already exist tracking the various small-cap indices therefore the case for giving money to a run-of-the-mill, low-skill small-cap manager is not strong.

– Is your skill repeatable going forward, including how dependent it might be on an environment, the presence of particular market participants or events, and on you yourself being around?

– Where along the risk axis are you positioned? The skill you have may be packaged in a way that is unattractive because the risk level at which you operate is too high or too low or too erratic.

and so on.

*there are of course provisos to this: an inappropriately chosen benchmark could suggest there is skill when in fact there is none. Example: a passive equity manager chooses (inappropriately, because it is not his default portfolio) to benchmark himself against cash. In this case the excess volatility is just equity vol and excess return just passive equity return. His apparently skilful management is a sham.

Hope you found my post interesting. As always, I welcome your comments. Until next week, happy trading!

Happy Trading,

PJ

I avoid stocks on the long side that exhibit long-term down trends, or stocks that are trading below their 200 day moving average. I chose 200 days because of its popularity with traders, but really my testing shows that anything from 100 days up to 400 days is effective. As a high level overlay nothing could be easier to apply. Basically, if you’re a short-term trader don’t open new long positions in stocks trading below their 200 day moving average.

The simple moving average is the average price over 200 rolling periods. Every time a new data point is added, the tail data point gets dropped; Hence the name moving average. This calculation has some very admirable properties. The first, when today’s price is performing better than its average price over the past 200 days, it will have a value greater than its moving average. Similarly, if today’s price is performing worse than its average price over the past 200 days, it will trade below its moving average. This mathematical fact guarantees that the price of any company facing financial strain will begin trading below its moving average. Said another way, every single company that has delisted from the JSE due to poor performance first saw its price trade below its moving average. Using this filter will significantly reduce the risk of being caught in stock headed for bankruptcy. ABIL (ABL) is a case in point. We removed the stock from our tradable universe in 2012, two years before it imploded. This turned out to be the right thing to do, protecting our capital from unnecessary risk. It’s worth noting however, that the stock continued to be a part of our shortable universe.

The second desirable attribute, because the moving average filter is applied at the individual stock level, it reduces risk long before the indices begin to show signs of weakness. In the final stages of a bull market we typically see only a handful of large cap stocks performing well. Because of the size of these stocks and their weight in the index, we often see the index continue to post new highs while the broad market begins to deteriorate. By employing a long-term moving average filter you allow your portfolio to continue to gain exposure to the strong stocks, while at the same time removing weak ones. You basically have a built-in breadth filter. The chart below of the JSE Top 40 nicely demonstrates this. The indicator in the top pane is the percentage of stocks trading above their 200 day moving average. The negative divergence with the index before the crisis began in 2008 is very clear. This simple overlay would have slowly started reducing risk by removing equities from the long side long before the crisis began, and despite new highs in the index.

As always, we like to see the proof! I ran a test this morning to compute the average five day returns for stocks trading above and below their 200 day moving averages. The results are very significant and based on well over 200 000 trades. In the short-term, you’re doing yourself an injustice by trading against this data. If you’re looking to reduce risk and improve your results then follow this simple rule: Avoid stocks on the long side if they’re trading below their 200 day moving average (experienced traders may consider shorting).

Average Five Day Returns

Above 200 day MA: **0.28%**

Below 200 day MA:** 0.18%**

As always, I welcome your comments and feedback.

Happy Trading,

PJ

With the launch of Trading Stocks just around the corner I thought that it would be fun this week to explore one of the quantified breadth filters that clients will have access to in our new platform. The indicator that I’ll feature this week falls into a set of indicators referred to as diffusion indicators. These belong to the breadth class of indicators because they include an entire set of equities in their calculation as opposed to a single equity. As a result they can be effectively used to analyse the internal strength of a market, analyse the degree to which the market is overbought/oversold and they work very well as high level risk filters to control position size and directional risk. I’ll be using these extensively on a daily basis trading a live account that you’ll be able to follow for free from the homepage of our new site. So without further ado let’s dig into our indicator.

*Are you looking for a calculated approach to trading that relies on statistics as opposed to human opinion and gut feel?*

*Do you have R15 000 to fund a trading account?*

*If you answered yes to the above then be sure to trial our new product for free on 1 August 2015!*

*Key Features:*

*• Big picture analysis giving you access to quantified metrics across 37 exchanges*

*• JSE market breadth analysis providing a quantified look at the JSE internal strength*

*• 120 000 quantified strategy variations – remove guesswork from your trading!*

*• Powerful quantified short-term stock rating system*

*• PJ’s daily battle plan where I’ll discuss how and why I’m using each quantified strategy daily*

*• Extremely powerful performance monitoring system synced precisely to your broker’s account*

*• Costs as little as R199 a month*

Equity prices tend to mean revert in the short-term. In other words, they tend to move from periods of lows to highs and vice versa. Our breadth indicator will look to capitalise on this tendency, but instead of analysing a single equity in isolation, we’ll view the entire liquid universe to get a sense of how stretched the market is in the short-term and therefore how likely it is to reverse. To test the effectiveness of our indicator I’ll apply it to the Satrix 40 ETF (JSE Top 40 ETF).

One way to exploit mean reversion by using market breadth is to analyse the percentage of stocks trading above/below a five day simple moving average. The basic premise is that when the percentage approaches 100% on either side of the moving average then the market is probably stretched in that direction and likely to reverse. For instance, if more than 90% of stocks are trading below their five day moving average then we’d take a long position in the Top 40 ETF in anticipation of the market reverting to more normal levels. Here are the precise rules that I used for my testing:

Long only in the Satrix Top 40

Entry: Percentage stocks above their five day moving average < 10% (Market oversold). Enter at Close.

Exit: Percentage stocks above their five day moving average > 50% (Market recovered). Exit at Close.

Despite the simplicity of the system, the quantified performance is fantastic. The model enjoyed a win rate of 79% and generated an average trade return of +1.81%. The average hold for a trade was 4.21 days. Although I personally wouldn’t trade this system on a standalone basis, it does offer tremendous value as an additional overlay in a more fully developed system. This is precisely how I’ll be using this indicator in my live trading. You’ll able to follow my analysis daily for free when we go live next month.

Thanks for reading. As always I welcome your comments.

Happy Trading,

PJ