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On the surface, this appears to produce a stable allocation, but is what you see always what you get? In our example below, a factor-based approach resulted in less fluctuation in risk contributions and total portfolio risk than a holdings-based approach. Our hypothetical portfolio is deed to resemble the relatively low-equity asset allocation an insurance company might provide. The target weights are shown in the exhibit below.
After a very tough for many quantitative strategies, particularly in market-neutral stock selection, 1 1 Close I choose market-neutral here as the cleanest example and a very relevant one todaybut the same ideas apply to any multi-factor process including traditional long-only multi-factor portfolios judged vs. This matters as the more intuitive something is the easier it is, all else equal, to stick with it.
A multi-factor process, by de, lacks simple one-liner explanations. To nobody's surprise I choose one value factor and one momentum factor for this example. Whenever I use a simple model for exposition I get paranoid that readers will think this is the state of our art.
The price momentum measure leaves off the immediate prior month as I first did in my dissertation and has become industry standard. This is a small nod towards how we do it in real life, but only a small and imperfect one.
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This is still only an illustrative model — though I think the intuition it supplies generalizes well. Given this weighting scheme, I run the risk of studying expensive-to-trade and expensive-to-short stocks making the potentially unrealistic. I also look only at gross returns. I do the same for one-year trailing momentum. Some : 7 7 Close As I discussed, keep in mind these hypothetical are gross returns, so on that front they are overstated. But, this model is a very simple subset of real-life models, so in this way they are possibly understated.
Source: AQR. For illustrative purposes only. Not representative of an actual portfolio AQR manages. Hypothetical data has inherent limitations, some of which are described in the disclosures.
Looking for the it factor
This hypothetical performance does not reflect the deduction of any trading or management fees, which as mentioned, would further reduce the actual return. Please see important disclosures at the end of this document. Show more. The value long-short portfolio has delivered 4. Its monthly correlation with the market portfolio from Ken French's website is 0.
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So, pretty darn market neutral. Doing the same for momentum you find a return of 2. Well, you do if you read the table! The stand-alone value and momentum market-neutral portfolios are Forming the portfolio on the average of the two factor ranks le to a long-short portfolio delivering 6. Such is the power of diversification. So, everyone would greatly prefer the combo portfolio 1. Indeed, if you allocated half of your wealth to each of those factor portfolios, you would get average returns halfway between them but still meaningful volatility reduction and thus Sharpe ratio increase.
Here we create the combo portfolio by combining value and momentum ranks and then picking the top and bottom thirds from the combination. In other words, we look for stocks with a combination of good characteristics, rather than combining stocks that may score highly on one but not the other. Well, I hope so.
Please read important disclosures at the end of this document. The ratio of 6. So, on this measure, the shorts are 4. Of course, being pure value comes with a cost. This momentum measure is the arithmetic average of equal weighted returns.
Furthermore it is total return including the risk-free rate. Finally, there is a look-ahead-bias in these s as simply being in our approximately top 1, universe lends a bias upwards to your prior year returns i. This is not a look-ahead-bias in the portfolio returns I report — just one that benignly affects the level of the momentum measure.
All of this is intuitive and the behavior of this portfolio will generally match that intuition. In a very big year for value in general measured in any reasonable wayit is almost guaranteed to rise.
But, of course, all this simple intuition gets you a 0. The short worst momentum averages Of course, momentum has the opposite problem to value.
So the high momentum longs averaged about 1. Clearly neither the pure value nor the pure momentum portfolio can have all good things i. But the pure momentum portfolio will also be very intuitive. In this case, this easy intuition comes with a Sharpe ratio of 0.
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As we know, the combo long-short portfolio is way better than stand-alone value or momentum as reported in our backtests here; but we think the evidence for this, in much broader backtests and through many years of real life trading, is staggering. As we saw above, the combo delivers about double the Sharpe ratio of the better of the two stand-alone portfolios with the same near zero actually slightly negative correlation to the long-only market and more return per dollar of the long-short portfolio. The value portfolio saw its expensive short side 4. For the combo portfolio you only get 2.
Again, pretty darn good, but nowhere near as good as single factor momentum.
But, of course, the key is the combo portfolio is ificantly better on both measures where the single factor portfolios were great on one but mildly to pretty bad on the other. It seems obvious that the intuition behind explaining the performance of a pure value or pure momentum portfolio would be much stronger than the combo portfolio.
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Out of the top 50 stocks again out of approximately 1, stocks in the combo portfolio there are 11 stocks that appear in the top 50 value portfolio long positions and it only goes up to 17 appearing in the top holdings of the value portfolio. Out of the top 50 stocks in the combo portfolio there are 12 stocks that appear in the top 50 stocks in the momentum portfolio and only 20 that appear in even the top holdings of the momentum portfolio.
If you really want an extreme stat there is only one stock in the combo portfolio that appears in the top 50 holdings for both value and momentum presumably a stock that was super-duper cheap a year ago and is still very cheap after a strong year.
But those are an important part of our process. And the logic still applies to factors that are merely uncorrelated.
All this goes to show how different the combo portfolio is from the single factor portfolios. The holdings are substantially different, another perspective on how intuition will be more difficult. That will be a good year for the combo portfolio. That will be a bad year for the combo. And it does represent a legitimate problem for some.
Consider the years after the GFC, prior towhen the value factor in general did quite poorly but our stock selection strategy did well. Of course, in reality, this is all a de feature, not a bug. Combining the als can lead to much better in our opinion, based on real life and extensive backtests long-term. When we also deliberately diversify across a large of stocks, any stock-specific stories are weakened and those are also often very intuitive!
And when we look at multi-asset portfolios beyond stock selection, e. But, that is the idea! And there is still intuition.
Looking for the intuition underlying multi-factor stock selection
That sum is what will not always come with screaming intuition. But we do have it for why we believe in the portfolio itself, and why the shown here have been strong over time. But we can and should take solace in knowing that there is strong intuition behind each factor, the portfolio, and why we believe it should work over time. Well, you own a bet on a set of characteristics of diversified portfolios — both long and short.
The short portfolio is a different conglomerate. So, what you own, or are betting on, is the difference in return between two diversified conglomerates with both conglomerates being in a matching set of industries that average 2x more expensive on the short vs. In other words, you can think of these things much like you would individual stocks. But as seen here and in many other places, it has worked way more often than it has not, it has worked out on net over time, and it has worked out way better than choosing your long and short conglomerates on a single more intuitively simple factor.
You actually own something and are short something you can get your head around. But, alas, it will still never be as simple as the single-factor or even single stock versions. It should just be better.