This blog is an adjunct to our Optimal Momentum investing website which can be found through the Website tab. It contains news and other information that may be of interest to momentum investors.

Sunday, January 12, 2014

Introducing Global Equities Momentum

I feature Global Equities Momentum (GEM) in my forthcoming book, so it is time to introduce it on our website. GEM is a simple but powerful model that switches between the S&P 500 Index, the MSCI All Country World Index ex-US, and the Barclays Capital US Aggregate Bond Index based on dual momentum. GEM is long just equities as long as their trend is positive based on absolute momentum. When the trend of stocks is down, GEM is only in bonds. My book will fully explore the characteristics of this model.

The long run risk premium (and expected return) of bonds is substantially lower than the risk premium of stocks, so stocks are the investment vehicle of choice as long as their trend is positive. There are, however, investors who, for fiduciary or other reasons, need to keep a permanent allocation to bonds. For this reason, we also track our model that maintains 60% in stocks and 40% in bonds. We call this Global Balanced Momentum (GBM). (Formally, we called it the Global Balanced Momentum Index.) GBM applies dual momentum to both stocks and bonds.

Finally, we continue to show the performance of dual momentum applied to US equity sectors. We call this Dual Momentum Sector Rotation (DMSR).  Please check out all three of these models that are now on the Performance Page of our website.

Past performance is no assurance of future returns. Please see our Disclaimer page for other disclosures.

Friday, October 18, 2013

Momentum Hierarchy

The chart below shows how dual momentum, absolute momentum, and relative momentum stack up against one another with our Dual Momentum Sector Rotation model. (No allowance has been made for transaction or other costs.) The light brown line at the bottom of the chart is the S&P500. The dark brown line just above it is an equally weighted average of all the sectors we use. Its shape is similar to the S&P 500, which means that volatility and drawdown are similar to the market's volatility and drawdown. Equal weighting shows modestly higher returns, due to mean reversion profits from monthly re-balancing and equal, rather than capitalization, weighting across sectors.

 Past performance is no assurance of future success. Please see our Disclaimer page.

The purple line shows relative strength momentum. It has higher profits than equal weighting, but retains the performance characteristics of the S&P500. Relative strength momentum typically boosts returns, but does little to reduce volatility or drawdown. It is the best known and most commonly used form of momentum investing.

When we get to the green line representing absolute momentum, things change. Returns are better than with relative momentum. More importantly, the dips representing larger drawdowns flatten out or disappear. Absolute momentum was out of stocks during all of the 2001-02 and most of the 2008-09 bear markets.

In the hierarchy of investment returns, equal weighting with re-balancing beats the S&P500. Relative strength momentum beats equal weighting. Absolute momentum not only beats relative strength momentum, but it is more stable and consistent. If you have to choose just one approach, then absolute momentum looks best. 

However, we are not limited to just one approach. The blue line shows what happens when you combine relative and absolute momentum. Returns improve further while retaining absolute momentum's more attractive risk profile. Dual momentum is where you really want to be.

Wednesday, October 2, 2013

Momentum...the Only Practical Anomaly?

Interest in momentum is growing as it gains recognition as the premier market anomaly. Our purpose here is not to report on every item or research finding related to momentum. We prefer instead to point out those that are most important or interesting often because they seem exceptionally good, or, occasionally, because they seem exceptionally bad.
One exceptionally good piece of research is the working paper by Israel and Moskowitz (I&M) called "The Role of Shorting, Firm Size, and Time on Market Anomalies." This paper has important implications not only for momentum investors, but also for those who are interested in size and value  investment tilts. I&M look at all three with respect to firm size, long or short market exposure, and results stability over time.

Most research papers on relative strength momentum present it on a long/short basis where you buy  winning stocks and short losing ones. In some papers, you can find some long-only results buried in a table somewhere. Except in my papers, it can be challenging to find visual representations or detailed analyses of long-only momentum. However, I&M offer insightful analysis of long-only momentum. It is important to look at long-only results for two reasons. First, most investors are interested only in the long side of the market. Second, in the words of I&M:

Using data over the last 86 years in the U.S. stock market (from 1926 to 2011) and over the last four decades in international stock markets and other asset classes (from 1972 to 2011), we find that the importance of shorting is inconsequential for all strategies when looking at raw returns. For an investor who cares only about raw returns, the return premia to size, value, and momentum are dominated by the contribution from long positions.

Therefore, even if you are open to shorting, it does not make much sense from a return perspective. 

I&M charts and tables show the top 30% of long-only momentum US stocks from 1927 through 2011 based on the past 12-month return skipping the most recent month. They also show the top 30% of value stocks using the standard book-to-market equity ratio, BE/ME, and the smallest 30% of US stocks based on market capitalization. 

Long-only momentum produces an annual information ratio almost three times larger than value or size. Long-only versions of size, value, and momentum produce positive alphas, but those of size and value are statistically weak and only exist in the second half of the data. Momentum delivers significant abnormal performance relative to the market and does so consistently across all the data.   

Looking at market alphas across decile spreads in the table above, there are no significant abnormal returns for size or value decile spreads over the entire 1926 to 2011 time period. Alphas for momentum decile portfolio spread returns, on the other hand, are statistically and economically large

The table above shows alphas across different 20-year periods. (Our recent post called Momentum Backtesting described why it is important to have an abundance of data to segment and use as a robustness check.) Here is what I&M say about these results:

Looking at these finer time slices, there is no significant size premium in any sub period after adjusting for the market. The value premium is positive in every sub period but is only statistically significant at the 5% level in one of the four 20-year periods, from 1970 to 1989. The momentum premium, however, is positive and statistically significant in every sub period, producing reliable alphas that range from 8.9 to 10.3% per year over the four sub periods.

Here is one more table from their paper that shows in more detail the influence size has on momentum and value:

In the words of I&M:

Looking across different sized firms, we find that the momentum premium is present and stable across all size groups—there is little evidence that momentum is substantially stronger among small cap stocks over the entire 86-year U.S. sample period. The value premium, on the other hand, is largely concentrated only among small stocks and is insignificant among the largest two quintiles of stocks (largest 40% of NYSE stocks). Our smallest size groupings of stocks contain mostly micro-cap stocks that may be difficult to trade and implement in a real-world portfolio. The smallest two groupings of stocks contain firms that are much smaller than firms in the Russell 2000 universe.

So there you have it. Momentum returns are strong, stable, and largely unaffected by size over the entire 86-year sample period (and in eight other markets and asset classes.) Long-only value (per the most commonly used metrics), on the other hand, shows positive alpha only among the smallest stocks and insignificant alphas among larger stocks. Since micro-cap stocks are more costly and difficult to trade, most investors, and particularly institutional ones, avoid this area of the market. Not only is momentum the "premier market anomaly" as per Fama & French, but, contrary to popular belief, it may be the only really practical anomaly.

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