Recent research suggests that equity factors exhibit positive autocorrelation, providing fertile ground for the application of trend-following strategies.
In this research note, we ask whether the same techniques can be applied to the active returns of long-only style portfolios.
We construct trend-following strategies on the active returns of popular MSCI style indices, including Value, Size, Momentum, Minimum Volatility, and Quality.
A naïve, equal-weight portfolio of style trend-following strategies generates an information ratio of 0.57.
The interpretation of this result is largely dependent upon an investor’s pre-conceived views of style investing, as the diversified trend-following approach generally under-performs a naïve, equal-weight portfolio of factors except during periods of significant and prolonged factor dislocation.
There have been a number of papers published in the last several years suggesting that positive autocorrelation in factor returns may be exploitable through time-series momentum / trend following. For example,
Ehsani and Linnainmaa (2017; revised 2019) document that “most factors exhibit positive autocorrelation with the average factor earning a monthly return of 2 basis points following a year of losses but 52 basis points following a positive year.”
Renz (2018) demonstrates that “risk premiums are significantly larger (lower) following recent uptrends (downtrends) in the underlying risk factor.”
While this research focuses mostly only long/short equity factors, it suggests that there may be opportunity for long-only style investors to improve their realized results as well. After all, long-only “smart beta” products can be thought of as simply a market-cap benchmark plus a dollar-neutral long/short portfolio of active bets.
Therefore, calculating the returns due to the active bets taken by the style is a rather trivial exercise: we can simply take the monthly returns of the long-only style index and subtract the returns of the long-only market-capitalization-weighted benchmark. The difference in returns will necessarily be due to the active bets.1
Below we plot the cumulative active returns for five popular equity styles: Value (MSCI USA Enhanced Value), Size (MSCI USA SMID), Momentum (MSCI USA Momentum), Minimum Volatility (MSCI USA Minimum Volatility), and Quality (MSCI USA Quality).
The active returns of these indices certainly rhyme with, but do not perfectly replicate, their corresponding long/short factor implementations. For example, while Momentum certainly exhibits strong, negative active returns from 6/2008 to 12/2009, the drawdown is nowhere near as severe as the “crash” that occurred in the pure long/short factor.
This is due to two facts:
The implied short side of the active bets is constrained by how far it can take certain holdings to zero. Therefore, long-only implementations tend to over-allocate towards top-quintile exposures rather than provide a balanced long/short allocation to top- and bottom-quintile exposures.
While the active bets form a long/short portfolio, the notional size of that portfolio is often substantially lower than the academic factor definitions (which, with the exception of betting-against-beta, more mostly assumed to have a notional exposure of 100% per leg). The active bets, on the other hand, have a notional size corresponding to the portfolio’s active share, which frequently hovers between 30-70% for most long-only style portfolios.
The implementation details of the long-only style portfolios and the long/short factor definitions may not perfectly match one another. As we have demonstrated a number of times in past research commentaries, these specification details can often swamp style returns in the short run, leading to meaningful cross-sectional dispersion in same-style performance.
Source: MSCI. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
Source: MSCI; AQR. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
Nevertheless, “rhymes but does not replicate” may be sufficient for long-only investors to still benefit from trend-following techniques.
In our test, we will go long the style / short the benchmark (i.e. long active returns) when prior N-month returns are positive and short the style / long the benchmark (i.e. short active returns) when prior N-month returns are negative. Portfolios are formed monthly at the end of each month. Performance results are reported in the table below for 1, 3, 6, 9, and 12-month lookback periods.
Annualized Return
Annualized Volatility
Information Ratio
Maximum Drawdown
Sample Size (Months)
1
Value
1.7%
6.1%
0.28
-15.1%
261
Size
-0.8%
8.2%
-0.10
-44.4%
303
Momentum
-0.2%
7.5%
-0.03
-21.3%
302
Minimum Volatility
-0.1%
5.7%
-0.01
-25.0%
375
Quality
1.3%
3.8%
0.35
-8.9%
302
3
Value
3.3%
6.0%
0.55
-15.5%
261
Size
1.1%
8.2%
0.13
-34.5%
303
Momentum
-0.8%
7.5%
-0.11
-38.0%
302
Minimum Volatility
0.7%
5.7%
0.13
-19.4%
375
Quality
0.9%
3.8%
0.24
-10.1%
302
6
Value
2.9%
6.0%
0.48
-21.0%
261
Size
1.7%
8.2%
0.20
-20.8%
303
Momentum
0.7%
7.5%
0.09
-28.8%
302
Minimum Volatility
0.5%
5.7%
0.09
-27.8%
375
Quality
0.6%
3.9%
0.16
-14.6%
302
9
Value
3.4%
6.0%
0.57
-14.8%
261
Size
2.0%
8.2%
0.24
-27.1%
303
Momentum
1.2%
7.5%
0.16
-23.4%
302
Minimum Volatility
0.9%
5.7%
0.15
-20.8%
375
Quality
0.3%
3.9%
0.07
-14.7%
302
12
Value
3.2%
6.0%
0.54
-11.2%
261
Size
1.8%
8.2%
0.22
-29.9%
303
Momentum
1.9%
7.5%
0.25
-20.0%
302
Minimum Volatility
1.4%
5.7%
0.24
-17.3%
375
Quality
1.3%
3.8%
0.34
-11.0%
302
Source: MSCI. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
Below we plot the equity curves of the 12-month time-series momentum strategy. We also plot a portfolio that takes a naïve equal-weight position across all five trend-following strategies. The naïve blend has an annualized return of 2.3%, an annualized volatility of 4.0%, and an information ratio of 0.57.
Source: MSCI. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
This analysis at least appears to provide a glimmer of hope for this idea. Of course, the analysis comes with several caveats:
We assume that investors can simultaneously generate signals and trade at month end, which may not be feasible for most.
We are analyzing index data, which may be different than the realized results of index-tracking ETFs.
We do not factor in trading costs such as impact, slippage, or commissions.
It is also important to point out that the per-style results vary dramatically. For example, trend-following on the size style has been in a material drawdown since 2006. Therefore, attempting to apply time-series momentum onto of a single style to manage style risk may only invite further strategy risk; this approach may be best applied with an ensemble of factors (and, likely, trend signals).
What this commentary has conveniently ignored, however, is that the appropriate benchmark for this approach is not zero. Rather, a more appropriate benchmark would be the long-only active returns of the styles themselves, as our default starting point is simply holding the styles long-only.
The results, when adjusted for our default of buy-and-hold, is much less convincing.
Source: MSCI. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
What is clear is that the strategy can now only out-perform when the style is under-performing the benchmark. When the portfolio invests in the style, our relative return versus the style is flat.
When a diversified trend-following portfolio is compared against a diversified long-only factor portfolio, we see the general hallmarks of a trend-following approach: value-add during periods of sustained drawdowns with decay thereafter. Trend-following on styles, then, may be more appropriate as a hedge against prolonged style under-performance; but we should expect a cost to that hedge.
Source: MSCI. Calculations by Newfound Research. Results are hypothetical. Results assume the reinvestment of all distributions. Results are gross of all fees, including, but not limited to, manager fees, transaction costs, and taxes. Past performance is not an indicator of future results. You cannot invest in an index.
For some styles, like Minimum Volatility, this appears to have helped relative performance drawdowns in periods like the dot-com bubble without too much subsequent give-up. Size, on the other hand, also benefited during the dot-com era, but subsequently suffered from significant trend-following whipsaw.
Conclusion
Recent research has suggested that equity style premia exhibit positive autocorrelation that can be exploited by trend followers. In this piece, we sought to explore whether this empirical evidence could be exploited by long-only investors by isolating the active returns of long-only style indices.
We found that a naïve 12-month time-series momentum strategy proved moderately effective at generating a timing strategy for switching between factor and benchmark exposure. Per-style results were fairly dramatic, and trend-following added substantial style risk of its own. However, diversification proved effective and an equal-weight portfolio of style trend-following strategies offered an information ratio of 0.57.
However, if we are already style proponents, a more relevant benchmark may be a long-only style portfolio. When our trend-following returns are taken in excess of this benchmark, results deflate dramatically, as the trend-following strategy can now only exploit periods when the style under-performs a market-capitalization-weighted index. Thus, for investors who already implement long-only styles in their portfolio, a trend-following overlay may serve to hedge periods of prolonged style drawdowns but will likely come with whipsaw cost which may drag down realized factor results.
In this commentary, we discuss what we mean by the phrase, “no pain, no premium.”
We re-frame the discussion of portfolio construction from one about returns to one about risk and argue that without risk, there should be no expectation of return.
With a risk-based framework, we argue that investors inherently act as insurance companies, earning a premium for bearing risk. This risk often manifests as significant negative skew and kurtosis in the distribution of asset returns.
We introduce the philosophical limits of diversification, arguing that we should not be able to eliminate risk from the portfolio without eliminating return as well.
Therefore, we should seek to eliminate uncompensated risks while diversifying across compensated ones.
We explore the three axes of diversification – what, how, and when – and demonstrate how thinking in a correlation-driven, payoff-driven, and opportunity-driven framework may help investors find better diversification.
1. Is it About Risk or Return?
For graduate school, I pursued my Masters of Science in Computational Finance at Carnegie Mellon University. One of the first degrees of its kind in the late 1990s, this financial engineering program is a cross-disciplinary collaboration between the finance, mathematics, statistics, and computer-science departments.
In practice, it was an intensive year-and-a-half study on the theoretical and practical considerations of pricing financial derivatives.
I do not recall quite when it struck me, but at some point I recognized a broader pattern at play in every assignment. The instruments we were pricing were always about the transference of risk in some capacity. Our goal was to identify that risk, figure out how to isolate and extract it, package it into the appropriate product type, and then price it for sale.
Risk was driving the entire equation. Pricing was all about understanding distribution of the potential payoffs and trying to identify “fair compensation” for the variety of risks and assumptions we were making.
For every buyer, there is a seller and vice versa and, at the end of the day, sellers who did not want risk and would have to compensate buyers to bear it.
1.1 Stocks for the Long Run
The idea that reward is compensation for risk is certainly not a new one. It is, more or less, the entire foundation of modern finance.
But sometimes, it seems, we forget it.
We are often presented with a return-based lens through which to evaluate the world of finance. Commonly reprinted are graphs like the one below, demonstrating century-long returns for stocks, bonds, and cash and accompanied by broad, sweeping generalizations like, “stocks for the long run.”
The truth is, if you plot anything on a log-axis over a long enough time horizon and draw it with a thick enough crayon, the line will eventually look pretty straight.
But if we zoom in to a horizon far more relevant to the lifecycle of most individual investors, we see a very different picture.
What we see is the realization of risk. We have to remember that the excess returns we expect to earn over the long run are compensation for bearing risk. And that risk needs to manifest, from time-to-time. Otherwise, if the probability of the risk being realized goes down, then so should the excess premium we expect to earn.
From a quantitative perspective, risk is often measured as volatility. In our opinion, that’s not quite right. We believe, given a long enough return history with enough realized risk events, risk can be better measured in a return’s distribution symmetry and fat-tailed-ness (i.e. “skew” and “kurtosis” respectively).
Below we plot the annualized excess real return distribution for U.S. equities over the last 100 years. We can see that the distribution is “leaning” to the right, indicating that large losses are more frequent than large gains.
We would argue that when we buy equities, what we are really buying is a risk. In particular, we are buying an uncertain stream of cash flows.
Now, this might seem a little weird. Why would we ever pay someone to bear their risk?
The answer is because, in many ways, we can think of equities as a swap of cashflows: one up-front bullet payment for the rights to an uncertain stream of future cash flows generated by the underlying business.
In theory, the price we pay today should be less than the net present value of all those future cash flows, with the difference representing the premium we expect to earn over time.
Uncertainty is the wedge between the values. Without uncertainty, no rational seller would give up their future cash flows for less than they are worth (or, if we do have an irrational seller, we would expect buyers to compete over those cashflows to the point they are fairly valued).
Thus, the premium will be driven both by certainty about the future cash flows (growth rate and duration) as well as the market’s appetite for bearing risk.
The more certain we are of those future cash flows or the higher the market’s appetite to bear risk, the smaller the expected premium should be.
1.2 “Funding Secured”
To get a better sense of the play between certainty and premium in the market, we can explore an example where we effectively collapse price into a binary “yes or no” event.
On August 7th, 2018, Elon Musk sent out the following tweets:
At the time he sent the tweet, Tesla shares were trading around approximately $365. The stock had opened around $340 that day and had jumped on news reporting that the Saudi sovereign fund had built a $2b stake in Tesla and some speculation about a potential buy-out.
Now let’s assume, for a moment, that Elon’s tweet said, “Deal struck to take Tesla private at $420, effectively immediately” What should the price of Tesla’s stock jump to? $420, of course.
Now Elon’s tweet merely said he was considering it. He also did not specify a timeline. But let’s consider two cases:
The market believes a deal will be struck to take Tesla at $420 in the near future.
The market does not believe Tesla will be taken private.
In the former case, the right price is approximately $420. In the latter case, the appropriate price is whatever the shares were trading at before the announcement.1
Thus, where price trades between the two points can be interpreted as to the market’s confidence in the deal being done.
Hence, I tweeted the following:
(Note that when I sent out the first tweet, I hadn’t realized trading had been halted in Tesla.)
Assuming the entire day’s move was attributed to the buyout news, a price change from $340 to $380 only represents a 50% move towards the buy-out price of $420. The market was basically saying, “we give this coin-flip odds.”
1.2 Well ‘Skews Me
While modern portfolio theory uses volatility as the measure of risk, the connection between excess realized premia and volatility is tenuous at best. It certainty falls apart in highly skewed, fat-tailed return distributions.
Rather, skewness appears to be a much better measure of risk for most financial assets. And when we look at equity markets around the globe, we see the same fact pattern emerge: return distributions with negative skew indicating that losses tend to be (much) bigger than gains.
2. You’re An Insurance Company
What this type of risk-based thinking all boils down to is that you – and your portfolio – are really acting as an insurance company of sorts.
When we purchase insurance, we are really transferring our associated risk to the insurance company. To incentivize them to bear the risk, we have to pay an annual premium.
Similarly, when we buy stocks, we are really trading a certain cashflow today (the price) for a stream of uncertain cash flows in the future. The discount between the price we pay and the net present value of future cash flows is the premium we expect to earn. And when we sell stocks, we are effectively paying that premium.
So in building our portfolios, we should think like an insurance company.
Like an insurance company, we want to diversify the premiums we earn. Not only do we want to diversify within a given type of insurance, but we probably also want to diversify the type of insurance we offer. And, in an ideal world, the type of insurance would be uncorrelated!
2.1 Diversifying with Bonds
Enter the most traditional portfolio diversifier: bonds. Typically considered to be a “safe” asset, if we look at them through the lens of real excess returns, we can see that bond returns also exhibit negative skew and fat tails.
This makes sense, as when we buy a bond we are still bearing all sorts of risks. Not only do we bear the risk of a default, but we also bear inflation risk and interest rate path-dependency risk.
With U.S. Treasuries, default risk is likely minimized (depending on your perspective), and the other two risks might be less correlated than the traditional risks (e.g. economic growth) we see with equities. So combining stocks and bonds should help us control skew, right?
Well, not quite. Below we plot the annualized excess real returns for a 60/40 portfolio.
We see that skew and kurtosis remain. What gives?
Well, one answer is that while a 60/40 portfolio might be close to balanced in the terms of notional dollar exposure to each asset, it is completely unbalanced from the perspective of residual volatility.
Below we plot the relative contribution to risk of stocks and bonds over time in a 60/40 portfolio.
Because the payout for bonds is far more certain than the payout for stocks, not only is the expected excess premium much lower, but volatility tends to be much lower as well. This means that the premium earned from holding bonds is not large enough to offset the losses realized in equities.
Savvy readers will recognize this as the driving thesis behind risk parity. To strike a balance, we need to allocate to stocks and bonds in such a manner that they provide equal contribution to portfolio risk.
Below, we plot the annual excess real return distribution for a stock/bond risk parity portfolio that is levered to a constant volatility target of 8%.
What do we see? Skew and fat tails remain. Perhaps the answer is simply that we need more diversification. While in practice this might mean buying different assets, in theory it means exposing ourselves to different types of risk sources that lead to uncertainty in the value of future cash flows. We enumerate a few below.
In traditional asset allocation, trying to isolate and add these different exposures is very difficult.
First, it is worth acknowledging that not every type of risk necessarily deserves to earn compensation. In theory, we should only be compensated for un-diversifiable risks.
Furthermore, many of these risks have time-varying correlations and magnitudes, and often collapse towards a single risk factor during crisis states of the world.
Yet we would argue that there is a deeper, philosophical limit we should consider.
3. The Philosophical Limits of Diversification
What we keep running up against is what we call the “philosophical limit of diversification.”
The simplest way to think about the limit is this: If we can diversify away all of our risk, we should not expect to earn any reward.
After all, if we found some magical combination of assets that eliminated downside risk in all future states of the world, we would have constructed an arbitrage. We could simply borrow at the risk-free rate, invest in the appropriate blend of assets, and reap our risk-free reward.
That is why years like 2018, when 90% of assets lose money, have to occur from time to time. Without the eventual realization of risk, there is no reason to expect return.
3.1 The Frustrating Law of Active Management
A corollary of this philosophical limit is what we like to call “The Frustrating Law of Active Management.”
We go further in depth into this idea in another commentary, but the basic idea follows: if an investment strategy is perceived both to have alpha and to be easy, investors will allocate to it and erode the associated premium.
How can a strategy be “hard”? Well, a manager might have a substantial informational or analytical edge. Or, the manager might have a structural moat, accessing trades others do not have the opportunity to pursue.
But for most well-known edges (e.g. most major style premia), “hard” is going to be behavioral. The strategy has to be hard enough to hold on to that it does not get arbitraged away. Which implies that,
For any disciplined investment approach to outperform over the long run, it must experience periods of underperformance in the short run.
This also implies that,
For any disciplined investment approach to underperform over the long run, it must experience periods of outperformance in the short run.
For active managers, the frustration is that not only does their investment approach have to under-perform from time-to-time, but bad strategies will have to out-perform. The latter may seem confusing until we consider that a purposefully bad strategy could simply be inverted to create a purposefully good one.2
And, as above, we cannot simply diversify our way out of the problem. After all, if there were a magic combination of active strategies that earned the same expected alpha but reduced the risk, everybody would pursue that combination.
4. Investment versus Investor Returns
So is the answer here to just, “suck it up?” Do we simply look at periods like 2000-2010 and say, “it’s the price we pay for the opportunity to earn long-run returns?”
We would argue both “yes” and “no.”
It all depends upon where an investor falls within their lifecycle. Young investors who are pursuing growth mandates may simply need to accept that skew and fat tails are the cost of earning the long-run premium. Too much diversification may lead to “failing slow.”
For investors in the later stages of their lifecycle, however, the math changes. Indeed, this is true for any individual or institution where withdrawals are concerned. When we have a withdrawal-driven mandate, it is the risk of “failing fast” that we need to concern ourselves with.
The problem is that investment-centric thinking often makes diversification seem foolish. To quote Brian Portnoy, “diversification means always having to say you’re sorry.”
Not only do we have to contend with the fact that the relative performance of the investments in our portfolio will vary wildly from one another year-to-year, but evidence suggests that so will the investor’s utility function.
Consider the graphic below, where the investor’s utility oscillates between relative (“I didn’t do as well as my peers!”) and absolute returns (“I lost money!”), making the diversified profile a consistent loser.
Source: BlackRock.
(3/14/2019 Update: It was pointed out to me that based upon the numbers in the table above, the total return reported the Diversified Portfolio is actually understated. Total return should be 202.4%, with $100K turning into $302,420.)
However, if we actually think about investor returns, rather than investment returns, the picture changes. Below we plot the growth of $1,000,000 since 2000 with a fixed $40,000 withdrawal. In this highly simplified example, we can begin to see the benefits of increased diversification.
Despite the philosophical limits of diversification, we clearly should not forgo it entirely. But what is the right framework to think about diversification and how it can be introduced into a portfolio?
5. The Three Axes of Diversification
At Newfound, we talk about three potential axes of diversification that investors can try to exploit.
We call these axes the what, the how, and the when axes, and they aim to capture what we invest in (“correlation driven”), how we make the decisions (“pay-off driven”), and when we make those decisions (“opportunity driven”).
Below, we explore each axis individually and how to might be able to contribute to a portfolio’s overall diversification profile.
5.1 What Axis (“Correlation Diversification”)
The “what” axis asks the question, “what are we investing in?” It captures the traditional notions of asset class and geographic diversification. As we have explored in this commentary, it also implicitly captures risk-based diversification.
We can also think of this axis as being responsible for “correlation-driven” diversification. As we will see, however, the empirical evidence of the effectiveness of this type of diversification is limited.
5.1.1 It’s Hard to Allocate Our Way Out of a Bear Market
Empirical evidence suggests that correlation-driven diversification is not tremendously effective at limited losses in crisis events. Consider the returns plotted below for a number of asset classes during 2008. We can see that by the end of the year, almost all had fallen between -20% to -50%.
As it turns out, most of the risk reduction benefits seen in a traditional asset allocation are not actually due to diversification benefits, but rather simply due to outright de-risking.
In their 2016 paper The Free Lunch Effect: The Value of Decoupling Diversification and Risk, Croce, Guinn and Robinson demonstrate that most of the risk reduction seen in moving from and all-stock portfolio to a balanced portfolio is simply due to the fact that bonds are less volatile than stocks.
That is not to say that de-risking is without its own merits. Outright de-risking a portfolio is simple way to reduce total loss potential and is one of the driving forces behind the benefits of glide-path investing’s ability to control sequence risk.
Investors looking to maintain a return profile while reducing risk through the benefits of diversification, however, may be disappointed.
In When Diversification Fails, Page and Panariello demonstrate that asset correlations tend to be bi-modal in nature. Unfortunately, the dynamics exhibited are the exact opposite of what we would like to see: diversification opportunity is ample in positive market states, but correlations tend to crash towards one during equity crises.
This does not make traditional diversification outright worthless, however, for growth-oriented investors.
Consider the table below from a paper titled, The Risk of Premiums, in which the author summarizes his findings about the statistical significance of different realized equity risk premia around the globe over different time horizons.
The five countries with stars on the left-hand side of the table have historically exhibited statistically significant risk premia across rolling 1-, 5-, 10-, and 20-year periods. Those with stars on the right did not exhibit statistically significant risk premia across any of the rolling periods.
It is important to remember that risk premia are expected, but by no means guaranteed. It is entirely possible that markets mis-estimate the frequency or magnitude with which risks manifest and fail to demand an adequately compensating premium.
Things have worked out exceptionally well for U.S. investors, but the same cannot be said for investors around the globe.
With the exception of explicit de-risking, what diversification may not necessarily provide much support in managing the left-tails of systematic risk factors. Nevertheless, what diversification may be critical in helping reduce exposure to idiosyncratic risks associated with a specific geographic region or asset class.
5.2 The How Axis – Payoff Diversification
The how axis asks the question, “how are we making our investment decisions.”
How need not be complex. Low-cost, tax-efficient passive asset allocation is a legitimate how.
But this axis also captures the variety of other active investment styles that can create their own, and often independent, return streams.
One might go so far as to call them “synthetic assets,” but most popular literature simply refers to them as “styles.” Popular categories include: value, momentum, carry, defensive (quality / low-volatility), trend, and event-driven.
The how axis is able to take the same what and create what are potentially unique return streams. The return profile of a currency momentum portfolio may be inherently different than a commodity value portfolio, both of which may offer diversification from traditional, economic risk factors that drive currency and commodity beta.
If the what axis captures correlation driven diversification, we would argue that the how axis captures pay-off driven diversification.
5.2.1 Style Diversification
In When Diversification Fails, Page and Panariello also found that correlations for many styles are bi-modal, but some may offer significant diversification in equity crisis states.
2018, however, once again proved that there are philosophical limits to the benefits of diversification. For styles to work over the long run, not only do there have to be periods where they fail individually, but there have to be periods where they fail simultaneously.
If we want to keep earning reward, we have to bear some risk in some potential state of the world.
It is no surprise, then, that it appears that most major styles appear to offer compensation for their own negative skew. In their 2014 paper Risk Premia: Asymmetric Tail Risks and Excess Returns, Lemperiere, Deremble, Nguyen, Seager, Potters and Bouchaud find that not only do most styles exhibit negative skew, but that there appears to be a positive relationship with skew and the style’s Sharpe ratio.
As with asset classes, return appears to be a compensation for bearing asymmetric risk.
The two exceptions in the graph are trend and equity value (Fama-French HML).
The authors of the paper note that the positive skew of equity value is somewhat problematic, as it implies it is an anomaly rather than a risk compensation. However, using monthly returns to recreate the above graph shifts the skew of equity value back to negative, implying perhaps that there is a somewhat regime-driven nature to value that needs to be further explored.
While the findings of Lemperiere, Deremble, Nguyen, Seager, Potters and Bouchaud (2016) imply that style premia are not exceptions to the “no pain, no premium” rule, we should not be dissuaded from considering the potential benefits of their incorporation within a portfolio.
After all, not only might we potentially benefit from the fact that their negative states might be somewhat independent of economic risk factors (acknowledging, as always, the philosophical limits of diversification), but the trading strategies themselves create varying payoff profiles that differ from one another.
By combining different asset classes and payoff functions, we may be able to create a higher quality of portfolio return.
For example, when we overlay a naive trend strategy on top of U.S. equities, the result converges towards a distribution where we simply miss the best and worst years. However, because the worst years tend to be worse than the best years are good, it leads to a less skewed distribution.
In effect, we’ve fought negative skew with positive skew.
At Newfound, we often say that “risk cannot be destroyed, but only transformed.” We tend to think of risk as a blob that is spread across future states of the world. When we push down on that blob in one future state, in effect “reducing risk,” it simply displaces to another state.
Trend may have historically helped offset losses during crisis events, but it can create drawdowns during reversal markets. Similarly, style / alternative premia may be able to harvest returns when traditional economic factors are going sideways, but may suffer during coincidental drawdowns like 2018.
That is why we repeat ad nauseam “diversify your diversifiers.”
5.2.3 Specification Risk
While the above discussion of how pertained to style risks, there is another form of risk worth briefly discussing: specification risk.
Specification risk acknowledges that two investors implementing two identical styles in theory may end up with very different results in practice. Style risk tells us that equity value managers struggled as a category in 2016; specification risk tells us how each manager did individually.
Whether we are compensated for bearing specification risk is up for debate and largely depends upon your personal view of a manager’s skill.
In the absence of a view of skill, what we find is that combining multiple managers tends to do little for a reduction in traditional portfolio volatility (except in highly heterogenous categories), but can tremendously help reduce portfolio skew as well as the dispersion in terminal wealth.
For example, below we generate a number of random 30-stock portfolios and plot their returns over the last decade.
We can see that while the results are highly correlated, the terminal wealth achieved varies dramatically.
If instead of just picking one manager we pick several – say 3 or 4 – we find that the potential dispersion in terminal wealth drops dramatically and our achieved outcome is far more certain.
We believe that the when axis may be one of the most important, yet overlooked opportunities for diversification in portfolio construction. So much so, we wrote a paper about it titled Rebalance Timing Luck: The Difference Between Hired and Fired.
The basic intuition behind this axis is that our realized portfolio results will be driven by the opportunities presented to us at the time we rebalance.
In many ways, diversification along the when axis can be thought of as opportunity-diversification.
For example, Blitz, van der Grient, and van Vliet demonstrated in their 2010 paper Fundamental Indexation: Rebalancing Assumptions and Performancethat the quarter in which an annually-rebalanced fundamental index is reconstituted can lead to significant performance disparity. For example, the choice to rebalance the portfolio in March versus September would have lead to a 1,000 basis point performance difference in 2009.
This difference was largely driven by the opportunities perceived by the systematic strategy at the time of rebalancing.
This risk is not limited to active portfolios. In the graph below we plot rolling 1-year return differences between two 60/40 portfolios, one of which is rebalanced at the end of each February and one that is rebalanced at the end of each August.
We can see that the rebalance in early 2009 lead to a 700 basis point gap in performance by spring 2010.
While we believe this has important implications for how research is conducted, benchmarks are constructed, and managers build portfolios, the more practical takeaway for investors is that they might benefit from choosing managers who rebalance on different schedules.
6. Summary
Investors often focus on returns, but it is important to keep in mind why we expect to earn those returns in the first place. We believe a risk-based mindset can help remind us that we expect to earn excess returns because we are willing to bear risk.
In many ways, we can think of ourselves and our portfolios as insurance companies: we collect premiums for bearing risk. Yet while we can we can seek to diversify the risks we insure, there are few truly independent risk factor and the premiums aren’t often large enough to offset large losses.
We also believe that there exist theoretical limits to diversification. If we eliminate risk through diversification, we also eliminate reward. In other words: no pain, no premium.
This does not inherently mean, however, we should just “suck it up.” The implications of risk-based thinking is dependent upon where we are in our investment lifecycle.
The primary risk of investors with growth mandates (e.g. investors early in their lifecycle) is “failing slow,” which is the failure to growth their capital sufficiently to outpace inflation or meet future liabilities. In this case, our aim should be to diversify as much as possible without overly de-risking the portfolio. With a risk-based mindset, it becomes clear why approaches like risk parity, when targeting an adequate volatility, may be philosophically superior to traditional asset allocation.
For investors taking withdrawals (e.g. those late in their lifecycle or endowments/pensions), the primary risk is “failing fast” from large drawdowns. Diversification is likely insufficient on its own and de-risking may be prudent. Diversifying payoff types and introducing positive skew styles – e.g. trend – may also benefit the investment plan by creating a more consistent return stream.
Yet we should acknowledge that even return opportunities available along the how axis appear to be driven largely by skew, re-emphasizing that without potential pain, there should be no premium.
In a rising rate environment, conventional wisdom says to shorten duration in bond portfolios.
Even as rates rise in general, the influence of central banks and expectations for inflation can create short term movements in the yield curve that can be exploited using systematic style premia.
Value, momentum, carry, and an explicit measure of the bond risk premium all produce strong absolute and risk-adjusted returns for timing duration.
Since these methods are reasonably diversified to each other, combining factors using either a mixed or integrated approach can mitigate short-term underperformance in any given factor leading to more robust duration timing.
In past research commentaries, we have demonstrated that the current level of interest rates is much more important than the future change in interest rates when it comes to long-term bond index returns[1].
That said, short-term changes in rates may present an opportunity for investors to enhance return or mitigate risk. Specifically, by timing our duration exposure, we can try to increase duration during periods of falling rates and decrease duration during periods of rising rates.
In timing our duration exposure, we are effectively trying to time the bond risk premium (“BRP”). The BRP is the expected extra return earned from holding longer-duration government bonds over shorter-term government bonds.
In theory, if investors are risk neutral, the return an investor receives from holding a current long-duration bond to maturity should be equivalent to the expected return of rolling 1-period bonds over the same horizon. For example, if we buy a 10-year bond today, our return should be equal to the return we would expect from annually rolling 1-year bond positions over the next 10 years.
Risk averse investors will require a premium for the uncertainty associated with rolling over the short-term bonds at uncertain future interest rates.
In an effort to time the BRP, we explore the tried-and-true style premia: value, carry, and momentum. We also seek to explicitly measure BRP and use it as a timing mechanism.
To test these methods, we will create long/short portfolios that trade a 10-year constant maturity U.S. Treasury index and a 3-month constant maturity U.S. Treasury index. While we do not expect most investors to implement these strategies in a long/short fashion, a positive return in the strategy will imply successful duration timing. Therefore, instead of implementing these strategies directly, we can use them to inform how much duration risk we should take (e.g. if a strategy is long a 10-year index and short a 3-month index, it implies a long-duration position and would inform us to extend duration risk within our long-only portfolio). In evaluating these results as a potential overlay, the average profit, volatility, and Sharpe ratio can be thought of as alpha, tracking error, and information ratio, respectively.
As a general warning, we should be cognizant of the fact that we know long duration was the right trade to make over the last three decades. As such, hindsight bias can play a big role in this sort of research, as we may be subtly biased towards approaches that are naturally long duration. In effort to combat this effect, we will attempt to stick to standard academic measures of value, carry, and momentum within this space (see, for example, Ilmanen (1997)[2]).
Timing with Value
Following the standard approach in most academic literature, we will use “real yield” as our proxy of bond valuation. To estimate real yield, we will use the current 10-year rate minus a survey-based estimate for 10-year inflation (from the Philadelphia Federal Reserve’s Survey of Professional Forecasters)[3].
If the real yield is positive (negative), we will go long (short) the 10-year and short (long) the 3-month. We will hold the portfolio for 1 year (using 12 overlapping portfolios).
It is worth noting that the value model has been predominately long duration for the first 25 years of the sample period. While real yield may make an appropriate cross-sectional value measure, it’s applicability as a time-series value measure is questionable given the lack of trades made by this strategy.
One potential solution is to perform a rolling z-score on the value measure, to determine relative richness versus some normalized local history. In at least one paper, we have seen a long-term “normal” level established as an anchor point. With the complete benefit of hindsight, however, we know that such an approach would ultimately load to a short-duration position over the last 15 years during the period of secular decline in real rates.
For example, Ilmanen and Sayood (2002)[4] compare real yield versus its previous-decade average when trading 7- to 10-year German Bunds. Expectedly, the result is non-profitable.
Timing with Momentum
How to measure momentum within fixed income seems to be up for some debate. Some measures include:
Change in bond yields (e.g. Ilmanen (1997))
Total return of individual bonds (e.g. Kolanovic and Wei (2015)[5] and Brooks and Moskowitz (2017)[6])
Total return of bond indices (or futures) (e.g. Asness, Moskowitz, and Pedersen (2013)[7], Durham (2013)[8], and Hurst, Ooi, Pedersen (2014)[9])
In our view, the approaches have varying trade-offs:
While empirical evidence suggests that nominal interest rates can exhibit secular trends, rate evolution is most frequently modeled as mean-reversionary. Our research suggests that very short-term momentum can be effective, but leads to a significant amount of turnover.
The total return of individual bonds makes sense if we plan on running a cross-sectional bond model (i.e. identifying individual bonds), but is less applicable if we want to implement with a constant maturity index.
The total return of a bond index may capture past returns that are attributable to securities that have been recently removed.
We think it is worth noting that the latter two methods can capture yield curve effects beyond shift, including roll return, steepening and curvature changes. In fact, momentum in general may even be able to capture other effects such as flight-to-safety and liquidity (supply-demand) factors. This may be a positive or negative thing depending on your view of where momentum is originating from.
As our intention is to ultimately invest using products that follow constant maturity indices, we choose to compare the total return of bond indices.
Specifically, we will compute the 12-1 month return of the 10-year index and subtract the 12-1 month return of the 3-month index. If the return is positive (negative), we will go long (short) the 10-year and short (long) the 3-month.
Timing with Carry
We define the carry to be the term spread (or slope) of the yield curve, measured as the 5-year rate minus the 2-year rate.
A steeper curve has two implications. First, if there is a premium for bearing duration risk, longer-dated bonds should offer a higher yield than shorter-dated bonds. Hence, we would expect a steeper curve to be correlated with a higher BRP.
Second, all else held equal, a steeper curve implies a higher roll return for the constant maturity index. So long as the spread is positive, we will remain invested in the longer duration bonds.
Similar to the value strategy, we can see that term-spread was largely positive over the entire period, favoring a long-duration position. Again, this calls into question the efficacy of using term spread as a timing model since we didn’t see much timing.
Similar to value, we could employ a z-scoring method or compare the measure to a long-term average. Ilmanen and Sayood (2002) find such an approach profitable in 7- to 10-year German Bunds. We similarly find comparing current term-spread versus its 10-year average to be a profitable strategy, though annualized return falls by 200bp. The increased number of trades, however, may give us more confidence in the sustainability of the model.
One complicating factor to the carry strategy is that rate steepness simultaneously captures both the expectation of rising short rates as well as an embedded risk premium. In particular, evidence suggests that mean-reverting rate expectations dominate steepness when short rates are exceptionally low or high. Anecdotally, this may be due to the fact that the front end of the curve is determined by central bank policy while the back end is determined by inflation expectations. In Expected Returns, Antti Ilmanen highlights that the steepness of the yield curve and a de-trended short-rate have an astoundingly high correlation of -0.79.
While a steep curve may be a positive sign for the roll return that can be captured (and our carry strategy), it may simultaneously be a negative sign if flattening is expected (which would erode the roll return). The fact that the term spread simultaneously captures both of these effects can lead to confusing interpretations.
We can see that, generally, term spread does a good job of predicting forward 12-month realized returns for our carry strategy, particularly post 2000. However, having two sets of expectations embedded into a single measure can lead to potentially poor interpretations in the extreme.
Explicitly Estimating the Bond Risk Premium
While value, momentum, and carry strategies employ different measures that seek to exploit the time-varying nature of the BRP, we can also try to explicitly measure the BRP itself. We mentioned in the introduction that the BRP is compensation that an investor demands to hold a long-dated bond instead of simply rolling short-dated bonds.
One way of approximating the BRP, then, is to subtract the expected average 1-year rate over the next decade from the current 10-year rate.
While the current 10-year rate is easy to find, the expected average 1-year rate over the next decade is a bit more complicated. Fortunately, the Philadelphia Federal Reserve’s Survey of Professional Forecasters asks for that explicit data point. Using this information, we can extract the BRP.
When the BRP is positive (negative) – implying that we expect to earn a positive (negative) return for bearing term risk – we will go long (short) the 10-year index and short (long) the 3-month index. We will hold the position for one year (using 12 overlapping portfolios).
Diversifying Style Premia
A benefit of implementing multiple timing strategies is that we have the potential to benefit from process diversification. A simple correlation matrix shows us, for example, that the returns of the BRP model are well diversified against those of the Momentum and Carry models.
BRP
Momentum
Value
Carry
BRP
1.00
0.35
0.76
0.37
Momentum
0.35
1.00
0.68
0.68
Value
0.76
0.68
1.00
0.73
Carry
0.37
0.68
0.73
1.00
One simple method of embracing this diversification is simply using a composite multi-factor approach: just dividing our capital among the four strategies equally.
We can also explore combining the strategies through an integrated method. In the composite method, weights are averaged together, often resulting in allocations canceling out, leaving the strategy less than fully invested. In the integrated method, weights are averaged together and then the direction of the implied trade is fully implemented (e.g. if the composite method says be 25% long the 10-year index and -25% short the 3-month index, the integrated method would go 100% long the 10-year and -100% short the 3-month). If the weights fully cancel out, the integrated portfolio remains unallocated.
We can see that while the integrated method significantly increases full-period returns (adding approximately 150bp per year), it does so with a commensurate amount of volatility, leading to nearly identical information ratios in the two approaches.
Did Timing Add Value?
In quantitative research, it pays to be skeptical of your own results. A question worth asking ourselves is, “did timing actually add value or did we simply identify a process that happened to give us a good average allocation profile?” In other words, is it possible we just data-mined our way to good average exposures?
For example, the momentum strategy had an average allocation that was 55% long the 10-year index and -55% short the 3-month index. Knowing that long-duration was the right bet to make over the last 25 years, it is entirely possible that it was the average allocation that added the value: timing may actually be detrimental.
We can test for this by explicitly creating indices that represent the average long-term allocations. Our timing models are labeled “Timing” while the average weight models are labeled “Strategic.”
CAGR
Volatility
Sharpe Ratio
Max Drawdown
BRP Strategic
2.75%
3.36%
0.82
7.17%
BRP Timing
3.89%
5.48%
0.71
14.00%
Momentum Strategic
3.54%
4.32%
0.82
9.09%
Momentum Timing
3.62%
7.20%
0.50
17.68%
Value Strategic
4.37%
5.38%
0.81
11.27%
Value Timing
5.75%
6.84%
0.84
15.17%
Carry Strategic
4.71%
5.80%
0.81
12.11%
Carry Timing
5.47%
6.97%
0.79
12.03%
While timing appears to add value from an absolute return perspective, in many cases it significantly increases volatility, reducing the resulting risk-adjusted return.
Attempting to rely on process diversification does not alleviate the issue either.
CAGR
Volatility
Sharpe Ratio
Max Drawdown
Composite Strategic
3.78%
4.63%
0.82
9.71%
Composite Timing
4.03%
5.26%
0.77
9.15%
As a more explicit test, we can also construct a long/short portfolio that goes long the timing strategy and short the strategic strategy. Statistically significant positive expectancy of this long/short would imply value added by timing above and beyond the average weights.
Unfortunately, in conducting such a test, we find that none of the timing models conclusively offer statistically significant benefits.
We want to be clear here that this does not mean timing did not add value. Rather, in this instance, timing does not seem to add value beyond the average strategic weights the timing models harvested.
One explanation for this result is that there was largely one regime over our testing period where long-duration was the correct bet. Therefore, there was little room for models to add value beyond just being net long duration – and in that sense, the models succeeded. However, this predominately long-duration position created strategic benchmark bogeys that were harder to beat. This test could really only show if the models detracted significantly from a long-duration benchmark. Ideally, we need to test these models in other market environments (geographies or different historical periods) to further assess their efficacy.
Robustness Testing: International Markets
We can try to allay our fears of overfitting by testing these methods on a different dataset. For example, we can run the momentum, value, and carry strategies on German Bund yields and see if the models are still effective.
Due to data accessibility, instead of switching between 10-year and 3-month indices, we will use 10-year and 2-year indices. We also slightly alter our strategy definitions:
Momentum: 12-1 month 10-year index return versus 12-1 month 2-year index return.
Value: 10-year yield minus trailing 1-year CPI change
Carry: 10-year yield minus 2-year yield
Given the regime concerns highlighted above, we will also test two other measures:
Value #2: Demeaned (using prior 10-year average) 10-year yield minus trailing 1-year CPI change
We can see similar results applying these methods with German rates as we saw with U.S. rates: momentum and both carry strategies remain successful while value fails when demeaned.
However, given that developed rates around the globe post-2008 were largely dominated by similar policies and factors, a healthy dose of skepticism is still well deserved.
Robustness Testing: Different Time Period
While success of these methods in an international market may bolster our confidence, it would be useful to test them during a period with very different interest rate and inflation evolutions. If we are again willing to slightly alter our definitions, we can take our U.S. tests back to the 1960s – 1980s.
Instead of switching between 10-year and 3-month indices, we will use 10-year and 1-year indices. Furthermore, we use the following methodology definitions:
Momentum: 12-1 month 10-year index return versus 12-1 month 1-year index return.
Value: 10-year yield minus trailing 1-year CPI change
Carry: 10-year yield minus 1-year yield
Value #2: Demeaned (using prior 10-year average) 10-year yield minus trailing 1-year CPI change
Over this period, all of the strategies exhibit statistically significant (95% confidence) positive annualized returns.[10]
That said, the value strategy suffers out of the gate, realizing a drawdown exceeding -25% during the 1960s through 6/1970, as 10-year rates climbed from 4% to nearly 8%. Over that period, prior 1-year realized inflation climbed from less than 1% to over 5%. With the nearly step-for-step increase in rates and inflation, the spread remained positive – and hence the strategy remained long duration. Without a better estimate of expected inflation (e.g. 5-year, 5-year forward inflation expectations, TIPs, or survey estimates)[11], value may be a failed methodology.
On the other hand, there is nothing that says that inflation expectations would have necessarily been more accurate in forecasting actual inflation. It is entirely plausible that future inflation was an unexpected surprise, and a more accurate model of inflation expectations would have kept real-yield elevated over the period.
Again, we find the power in diversification. While value had a loss of approximately -25% during the initial hikes, momentum was up 12% and carry was flat. Diversifying across all three methods would leave an investor with a loss of approximately -4.3%: certainly not a confidence builder for a decade of (mis-)timing decisions, but not catastrophic from a portfolio perspective.[12]
Conclusion
With fear of rising rates high, shortening bond during might be a gut reaction. However, even as rates rise in general, the influence of central banks and expectations for inflation can create short term movements in the yield curve that can potentially be exploited using style premia.
We find that value, momentum, carry, and an explicit measure of the bond risk premium all produce strong absolute and risk-adjusted returns for timing duration. The academic and empirical evidence of these factors in a variety of asset classes gives us confidence that there are behavioral reasons to expect that style premia will persist over long enough periods. Combining multiple factors into a portfolio can harness the benefits of diversification and smooth out the short-term fluctuations that can lead to emotion-driven decisions.
Our in-sample testing period, however, leaves much to be desired. Dominated largely by a single regime that benefited long-duration trades, all of the timing models harvested average weights that were net-long duration. Our research shows that the timing models did not add any statistically meaningful value above-and-beyond these average weights. Caveat emptor: without further testing in different geographies or interest rate regimes – and despite our best efforts to use simple, industry-standard models – these results may be the result of data mining.
As a robustness test, we run value, momentum, and carry strategies for German Bund yields and over the period of the 1960s-1980s within the United States. While we continue to see success to momentum and carry, we find that the value method may prove to be too blunt an instrument for timing (or we may simply need a better measure as our anchor for value).
Nevertheless, we believe that utilizing systematic, factor-based methods for making duration changes in a portfolio can be a way to adapt to the market environment and manage risk without relying solely on our own judgements or those we hear in the media.
As inspiration for future research, Brooks and Moskowitz (2017)[13] recently demonstrated that style premia – i.e. momentum, value, and carry strategies – provide a better description of bond risk premia than traditional model factors. Interestingly, they find that not only are momentum, value, and carry predictive when applied to the level of the yield curve, but also when applied to slope and curvature positions. While this research focuses on the cross-section of government bond returns across 13 countries, there may be important implications for timing models as well.
No Pain, No Premium
By Corey Hoffstein
On February 4, 2019
In Popular, Risk & Style Premia, Risk Management, Weekly Commentary
Summary
1. Is it About Risk or Return?
For graduate school, I pursued my Masters of Science in Computational Finance at Carnegie Mellon University. One of the first degrees of its kind in the late 1990s, this financial engineering program is a cross-disciplinary collaboration between the finance, mathematics, statistics, and computer-science departments.
In practice, it was an intensive year-and-a-half study on the theoretical and practical considerations of pricing financial derivatives.
I do not recall quite when it struck me, but at some point I recognized a broader pattern at play in every assignment. The instruments we were pricing were always about the transference of risk in some capacity. Our goal was to identify that risk, figure out how to isolate and extract it, package it into the appropriate product type, and then price it for sale.
Risk was driving the entire equation. Pricing was all about understanding distribution of the potential payoffs and trying to identify “fair compensation” for the variety of risks and assumptions we were making.
For every buyer, there is a seller and vice versa and, at the end of the day, sellers who did not want risk and would have to compensate buyers to bear it.
1.1 Stocks for the Long Run
The idea that reward is compensation for risk is certainly not a new one. It is, more or less, the entire foundation of modern finance.
But sometimes, it seems, we forget it.
We are often presented with a return-based lens through which to evaluate the world of finance. Commonly reprinted are graphs like the one below, demonstrating century-long returns for stocks, bonds, and cash and accompanied by broad, sweeping generalizations like, “stocks for the long run.”
The truth is, if you plot anything on a log-axis over a long enough time horizon and draw it with a thick enough crayon, the line will eventually look pretty straight.
But if we zoom in to a horizon far more relevant to the lifecycle of most individual investors, we see a very different picture.
What we see is the realization of risk. We have to remember that the excess returns we expect to earn over the long run are compensation for bearing risk. And that risk needs to manifest, from time-to-time. Otherwise, if the probability of the risk being realized goes down, then so should the excess premium we expect to earn.
From a quantitative perspective, risk is often measured as volatility. In our opinion, that’s not quite right. We believe, given a long enough return history with enough realized risk events, risk can be better measured in a return’s distribution symmetry and fat-tailed-ness (i.e. “skew” and “kurtosis” respectively).
Below we plot the annualized excess real return distribution for U.S. equities over the last 100 years. We can see that the distribution is “leaning” to the right, indicating that large losses are more frequent than large gains.
We would argue that when we buy equities, what we are really buying is a risk. In particular, we are buying an uncertain stream of cash flows.
Now, this might seem a little weird. Why would we ever pay someone to bear their risk?
The answer is because, in many ways, we can think of equities as a swap of cashflows: one up-front bullet payment for the rights to an uncertain stream of future cash flows generated by the underlying business.
In theory, the price we pay today should be less than the net present value of all those future cash flows, with the difference representing the premium we expect to earn over time.
Uncertainty is the wedge between the values. Without uncertainty, no rational seller would give up their future cash flows for less than they are worth (or, if we do have an irrational seller, we would expect buyers to compete over those cashflows to the point they are fairly valued).
Thus, the premium will be driven both by certainty about the future cash flows (growth rate and duration) as well as the market’s appetite for bearing risk.
The more certain we are of those future cash flows or the higher the market’s appetite to bear risk, the smaller the expected premium should be.
1.2 “Funding Secured”
To get a better sense of the play between certainty and premium in the market, we can explore an example where we effectively collapse price into a binary “yes or no” event.
On August 7th, 2018, Elon Musk sent out the following tweets:
At the time he sent the tweet, Tesla shares were trading around approximately $365. The stock had opened around $340 that day and had jumped on news reporting that the Saudi sovereign fund had built a $2b stake in Tesla and some speculation about a potential buy-out.
Now let’s assume, for a moment, that Elon’s tweet said, “Deal struck to take Tesla private at $420, effectively immediately” What should the price of Tesla’s stock jump to? $420, of course.
Now Elon’s tweet merely said he was considering it. He also did not specify a timeline. But let’s consider two cases:
In the former case, the right price is approximately $420. In the latter case, the appropriate price is whatever the shares were trading at before the announcement.1
Thus, where price trades between the two points can be interpreted as to the market’s confidence in the deal being done.
Hence, I tweeted the following:
(Note that when I sent out the first tweet, I hadn’t realized trading had been halted in Tesla.)
Assuming the entire day’s move was attributed to the buyout news, a price change from $340 to $380 only represents a 50% move towards the buy-out price of $420. The market was basically saying, “we give this coin-flip odds.”
1.2 Well ‘Skews Me
While modern portfolio theory uses volatility as the measure of risk, the connection between excess realized premia and volatility is tenuous at best. It certainty falls apart in highly skewed, fat-tailed return distributions.
Rather, skewness appears to be a much better measure of risk for most financial assets. And when we look at equity markets around the globe, we see the same fact pattern emerge: return distributions with negative skew indicating that losses tend to be (much) bigger than gains.
2. You’re An Insurance Company
What this type of risk-based thinking all boils down to is that you – and your portfolio – are really acting as an insurance company of sorts.
When we purchase insurance, we are really transferring our associated risk to the insurance company. To incentivize them to bear the risk, we have to pay an annual premium.
Similarly, when we buy stocks, we are really trading a certain cashflow today (the price) for a stream of uncertain cash flows in the future. The discount between the price we pay and the net present value of future cash flows is the premium we expect to earn. And when we sell stocks, we are effectively paying that premium.
So in building our portfolios, we should think like an insurance company.
Like an insurance company, we want to diversify the premiums we earn. Not only do we want to diversify within a given type of insurance, but we probably also want to diversify the type of insurance we offer. And, in an ideal world, the type of insurance would be uncorrelated!
2.1 Diversifying with Bonds
Enter the most traditional portfolio diversifier: bonds. Typically considered to be a “safe” asset, if we look at them through the lens of real excess returns, we can see that bond returns also exhibit negative skew and fat tails.
This makes sense, as when we buy a bond we are still bearing all sorts of risks. Not only do we bear the risk of a default, but we also bear inflation risk and interest rate path-dependency risk.
With U.S. Treasuries, default risk is likely minimized (depending on your perspective), and the other two risks might be less correlated than the traditional risks (e.g. economic growth) we see with equities. So combining stocks and bonds should help us control skew, right?
Well, not quite. Below we plot the annualized excess real returns for a 60/40 portfolio.
We see that skew and kurtosis remain. What gives?
Well, one answer is that while a 60/40 portfolio might be close to balanced in the terms of notional dollar exposure to each asset, it is completely unbalanced from the perspective of residual volatility.
Below we plot the relative contribution to risk of stocks and bonds over time in a 60/40 portfolio.
Because the payout for bonds is far more certain than the payout for stocks, not only is the expected excess premium much lower, but volatility tends to be much lower as well. This means that the premium earned from holding bonds is not large enough to offset the losses realized in equities.
Savvy readers will recognize this as the driving thesis behind risk parity. To strike a balance, we need to allocate to stocks and bonds in such a manner that they provide equal contribution to portfolio risk.
Below, we plot the annual excess real return distribution for a stock/bond risk parity portfolio that is levered to a constant volatility target of 8%.
What do we see? Skew and fat tails remain. Perhaps the answer is simply that we need more diversification. While in practice this might mean buying different assets, in theory it means exposing ourselves to different types of risk sources that lead to uncertainty in the value of future cash flows. We enumerate a few below.
In traditional asset allocation, trying to isolate and add these different exposures is very difficult.
First, it is worth acknowledging that not every type of risk necessarily deserves to earn compensation. In theory, we should only be compensated for un-diversifiable risks.
Furthermore, many of these risks have time-varying correlations and magnitudes, and often collapse towards a single risk factor during crisis states of the world.
Yet we would argue that there is a deeper, philosophical limit we should consider.
3. The Philosophical Limits of Diversification
What we keep running up against is what we call the “philosophical limit of diversification.”
The simplest way to think about the limit is this: If we can diversify away all of our risk, we should not expect to earn any reward.
After all, if we found some magical combination of assets that eliminated downside risk in all future states of the world, we would have constructed an arbitrage. We could simply borrow at the risk-free rate, invest in the appropriate blend of assets, and reap our risk-free reward.
That is why years like 2018, when 90% of assets lose money, have to occur from time to time. Without the eventual realization of risk, there is no reason to expect return.
3.1 The Frustrating Law of Active Management
A corollary of this philosophical limit is what we like to call “The Frustrating Law of Active Management.”
We go further in depth into this idea in another commentary, but the basic idea follows: if an investment strategy is perceived both to have alpha and to be easy, investors will allocate to it and erode the associated premium.
How can a strategy be “hard”? Well, a manager might have a substantial informational or analytical edge. Or, the manager might have a structural moat, accessing trades others do not have the opportunity to pursue.
But for most well-known edges (e.g. most major style premia), “hard” is going to be behavioral. The strategy has to be hard enough to hold on to that it does not get arbitraged away. Which implies that,
This also implies that,
For active managers, the frustration is that not only does their investment approach have to under-perform from time-to-time, but bad strategies will have to out-perform. The latter may seem confusing until we consider that a purposefully bad strategy could simply be inverted to create a purposefully good one.2
And, as above, we cannot simply diversify our way out of the problem. After all, if there were a magic combination of active strategies that earned the same expected alpha but reduced the risk, everybody would pursue that combination.
4. Investment versus Investor Returns
So is the answer here to just, “suck it up?” Do we simply look at periods like 2000-2010 and say, “it’s the price we pay for the opportunity to earn long-run returns?”
We would argue both “yes” and “no.”
It all depends upon where an investor falls within their lifecycle. Young investors who are pursuing growth mandates may simply need to accept that skew and fat tails are the cost of earning the long-run premium. Too much diversification may lead to “failing slow.”
For investors in the later stages of their lifecycle, however, the math changes. Indeed, this is true for any individual or institution where withdrawals are concerned. When we have a withdrawal-driven mandate, it is the risk of “failing fast” that we need to concern ourselves with.
The problem is that investment-centric thinking often makes diversification seem foolish. To quote Brian Portnoy, “diversification means always having to say you’re sorry.”
Not only do we have to contend with the fact that the relative performance of the investments in our portfolio will vary wildly from one another year-to-year, but evidence suggests that so will the investor’s utility function.
Consider the graphic below, where the investor’s utility oscillates between relative (“I didn’t do as well as my peers!”) and absolute returns (“I lost money!”), making the diversified profile a consistent loser.
Source: BlackRock.
(3/14/2019 Update: It was pointed out to me that based upon the numbers in the table above, the total return reported the Diversified Portfolio is actually understated. Total return should be 202.4%, with $100K turning into $302,420.)
However, if we actually think about investor returns, rather than investment returns, the picture changes. Below we plot the growth of $1,000,000 since 2000 with a fixed $40,000 withdrawal. In this highly simplified example, we can begin to see the benefits of increased diversification.
Despite the philosophical limits of diversification, we clearly should not forgo it entirely. But what is the right framework to think about diversification and how it can be introduced into a portfolio?
5. The Three Axes of Diversification
At Newfound, we talk about three potential axes of diversification that investors can try to exploit.
We call these axes the what, the how, and the when axes, and they aim to capture what we invest in (“correlation driven”), how we make the decisions (“pay-off driven”), and when we make those decisions (“opportunity driven”).
Below, we explore each axis individually and how to might be able to contribute to a portfolio’s overall diversification profile.
5.1 What Axis (“Correlation Diversification”)
The “what” axis asks the question, “what are we investing in?” It captures the traditional notions of asset class and geographic diversification. As we have explored in this commentary, it also implicitly captures risk-based diversification.
We can also think of this axis as being responsible for “correlation-driven” diversification. As we will see, however, the empirical evidence of the effectiveness of this type of diversification is limited.
5.1.1 It’s Hard to Allocate Our Way Out of a Bear Market
Empirical evidence suggests that correlation-driven diversification is not tremendously effective at limited losses in crisis events. Consider the returns plotted below for a number of asset classes during 2008. We can see that by the end of the year, almost all had fallen between -20% to -50%.
As it turns out, most of the risk reduction benefits seen in a traditional asset allocation are not actually due to diversification benefits, but rather simply due to outright de-risking.
In their 2016 paper The Free Lunch Effect: The Value of Decoupling Diversification and Risk, Croce, Guinn and Robinson demonstrate that most of the risk reduction seen in moving from and all-stock portfolio to a balanced portfolio is simply due to the fact that bonds are less volatile than stocks.
That is not to say that de-risking is without its own merits. Outright de-risking a portfolio is simple way to reduce total loss potential and is one of the driving forces behind the benefits of glide-path investing’s ability to control sequence risk.
Investors looking to maintain a return profile while reducing risk through the benefits of diversification, however, may be disappointed.
In When Diversification Fails, Page and Panariello demonstrate that asset correlations tend to be bi-modal in nature. Unfortunately, the dynamics exhibited are the exact opposite of what we would like to see: diversification opportunity is ample in positive market states, but correlations tend to crash towards one during equity crises.
This does not make traditional diversification outright worthless, however, for growth-oriented investors.
Consider the table below from a paper titled, The Risk of Premiums, in which the author summarizes his findings about the statistical significance of different realized equity risk premia around the globe over different time horizons.
The five countries with stars on the left-hand side of the table have historically exhibited statistically significant risk premia across rolling 1-, 5-, 10-, and 20-year periods. Those with stars on the right did not exhibit statistically significant risk premia across any of the rolling periods.
It is important to remember that risk premia are expected, but by no means guaranteed. It is entirely possible that markets mis-estimate the frequency or magnitude with which risks manifest and fail to demand an adequately compensating premium.
Things have worked out exceptionally well for U.S. investors, but the same cannot be said for investors around the globe.
With the exception of explicit de-risking, what diversification may not necessarily provide much support in managing the left-tails of systematic risk factors. Nevertheless, what diversification may be critical in helping reduce exposure to idiosyncratic risks associated with a specific geographic region or asset class.
5.2 The How Axis – Payoff Diversification
The how axis asks the question, “how are we making our investment decisions.”
How need not be complex. Low-cost, tax-efficient passive asset allocation is a legitimate how.
But this axis also captures the variety of other active investment styles that can create their own, and often independent, return streams.
One might go so far as to call them “synthetic assets,” but most popular literature simply refers to them as “styles.” Popular categories include: value, momentum, carry, defensive (quality / low-volatility), trend, and event-driven.
The how axis is able to take the same what and create what are potentially unique return streams. The return profile of a currency momentum portfolio may be inherently different than a commodity value portfolio, both of which may offer diversification from traditional, economic risk factors that drive currency and commodity beta.
If the what axis captures correlation driven diversification, we would argue that the how axis captures pay-off driven diversification.
5.2.1 Style Diversification
In When Diversification Fails, Page and Panariello also found that correlations for many styles are bi-modal, but some may offer significant diversification in equity crisis states.
2018, however, once again proved that there are philosophical limits to the benefits of diversification. For styles to work over the long run, not only do there have to be periods where they fail individually, but there have to be periods where they fail simultaneously.
If we want to keep earning reward, we have to bear some risk in some potential state of the world.
It is no surprise, then, that it appears that most major styles appear to offer compensation for their own negative skew. In their 2014 paper Risk Premia: Asymmetric Tail Risks and Excess Returns, Lemperiere, Deremble, Nguyen, Seager, Potters and Bouchaud find that not only do most styles exhibit negative skew, but that there appears to be a positive relationship with skew and the style’s Sharpe ratio.
As with asset classes, return appears to be a compensation for bearing asymmetric risk.
The two exceptions in the graph are trend and equity value (Fama-French HML).
The authors of the paper note that the positive skew of equity value is somewhat problematic, as it implies it is an anomaly rather than a risk compensation. However, using monthly returns to recreate the above graph shifts the skew of equity value back to negative, implying perhaps that there is a somewhat regime-driven nature to value that needs to be further explored.
Trend, on the other hand, has long-been established to exhibit positive skew. Indeed, it may very well be a mathematical byproduct of the trading strategy itself rather than an anomaly.
5.2.2 Payoff Diversification
While the findings of Lemperiere, Deremble, Nguyen, Seager, Potters and Bouchaud (2016) imply that style premia are not exceptions to the “no pain, no premium” rule, we should not be dissuaded from considering the potential benefits of their incorporation within a portfolio.
After all, not only might we potentially benefit from the fact that their negative states might be somewhat independent of economic risk factors (acknowledging, as always, the philosophical limits of diversification), but the trading strategies themselves create varying payoff profiles that differ from one another.
By combining different asset classes and payoff functions, we may be able to create a higher quality of portfolio return.
For example, when we overlay a naive trend strategy on top of U.S. equities, the result converges towards a distribution where we simply miss the best and worst years. However, because the worst years tend to be worse than the best years are good, it leads to a less skewed distribution.
In effect, we’ve fought negative skew with positive skew.
At Newfound, we often say that “risk cannot be destroyed, but only transformed.” We tend to think of risk as a blob that is spread across future states of the world. When we push down on that blob in one future state, in effect “reducing risk,” it simply displaces to another state.
Trend may have historically helped offset losses during crisis events, but it can create drawdowns during reversal markets. Similarly, style / alternative premia may be able to harvest returns when traditional economic factors are going sideways, but may suffer during coincidental drawdowns like 2018.
Source: PIMCO
That is why we repeat ad nauseam “diversify your diversifiers.”
5.2.3 Specification Risk
While the above discussion of how pertained to style risks, there is another form of risk worth briefly discussing: specification risk.
Specification risk acknowledges that two investors implementing two identical styles in theory may end up with very different results in practice. Style risk tells us that equity value managers struggled as a category in 2016; specification risk tells us how each manager did individually.
Whether we are compensated for bearing specification risk is up for debate and largely depends upon your personal view of a manager’s skill.
In the absence of a view of skill, what we find is that combining multiple managers tends to do little for a reduction in traditional portfolio volatility (except in highly heterogenous categories), but can tremendously help reduce portfolio skew as well as the dispersion in terminal wealth.
For example, below we generate a number of random 30-stock portfolios and plot their returns over the last decade.
We can see that while the results are highly correlated, the terminal wealth achieved varies dramatically.
If instead of just picking one manager we pick several – say 3 or 4 – we find that the potential dispersion in terminal wealth drops dramatically and our achieved outcome is far more certain.
You can read more on this topic in our past commentary Is Multi-Manager Diversification Worth It?
5.3 When Axis
We believe that the when axis may be one of the most important, yet overlooked opportunities for diversification in portfolio construction. So much so, we wrote a paper about it titled Rebalance Timing Luck: The Difference Between Hired and Fired.
The basic intuition behind this axis is that our realized portfolio results will be driven by the opportunities presented to us at the time we rebalance.
In many ways, diversification along the when axis can be thought of as opportunity-diversification.
For example, Blitz, van der Grient, and van Vliet demonstrated in their 2010 paper Fundamental Indexation: Rebalancing Assumptions and Performance that the quarter in which an annually-rebalanced fundamental index is reconstituted can lead to significant performance disparity. For example, the choice to rebalance the portfolio in March versus September would have lead to a 1,000 basis point performance difference in 2009.
This difference was largely driven by the opportunities perceived by the systematic strategy at the time of rebalancing.
This risk is not limited to active portfolios. In the graph below we plot rolling 1-year return differences between two 60/40 portfolios, one of which is rebalanced at the end of each February and one that is rebalanced at the end of each August.
We can see that the rebalance in early 2009 lead to a 700 basis point gap in performance by spring 2010.
While we believe this has important implications for how research is conducted, benchmarks are constructed, and managers build portfolios, the more practical takeaway for investors is that they might benefit from choosing managers who rebalance on different schedules.
6. Summary
Investors often focus on returns, but it is important to keep in mind why we expect to earn those returns in the first place. We believe a risk-based mindset can help remind us that we expect to earn excess returns because we are willing to bear risk.
In many ways, we can think of ourselves and our portfolios as insurance companies: we collect premiums for bearing risk. Yet while we can we can seek to diversify the risks we insure, there are few truly independent risk factor and the premiums aren’t often large enough to offset large losses.
We also believe that there exist theoretical limits to diversification. If we eliminate risk through diversification, we also eliminate reward. In other words: no pain, no premium.
This does not inherently mean, however, we should just “suck it up.” The implications of risk-based thinking is dependent upon where we are in our investment lifecycle.
The primary risk of investors with growth mandates (e.g. investors early in their lifecycle) is “failing slow,” which is the failure to growth their capital sufficiently to outpace inflation or meet future liabilities. In this case, our aim should be to diversify as much as possible without overly de-risking the portfolio. With a risk-based mindset, it becomes clear why approaches like risk parity, when targeting an adequate volatility, may be philosophically superior to traditional asset allocation.
For investors taking withdrawals (e.g. those late in their lifecycle or endowments/pensions), the primary risk is “failing fast” from large drawdowns. Diversification is likely insufficient on its own and de-risking may be prudent. Diversifying payoff types and introducing positive skew styles – e.g. trend – may also benefit the investment plan by creating a more consistent return stream.
Yet we should acknowledge that even return opportunities available along the how axis appear to be driven largely by skew, re-emphasizing that without potential pain, there should be no premium.