resilience, not stability

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Monetary Policy and Financial Markets: A “Real Rates” Lens

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In recent years, central banks on both sides of the Atlantic have implemented a raft of monetary policy initiatives that many people view as having no precedent in history. This opinion is understandable when compared to recent history – During the Great Moderation, monetary policy was largely restricted to adjustments in short-term nominal rates. But when viewed in the context of the longer history of fiat currency monetary policy, almost every policy implemented by central banks during this crisis has a historical precedent. In this post, I analyse fiat currency monetary policy (conventional or unconventional) as an attempt to influence the real interest rate curve under the constraint of inflation and employment/GDP targets – this is not intended to be a comprehensive theory, simply a lens that I find useful in analysing the impact of monetary policy.

The primary dilemma faced by governments today is the tension between the need to rein in government indebtedness in the long run and stimulate economic growth in the short run. The task of stimulating growth is complicated by the high levels of consumer indebtedness. There are no easy solutions to this problem – reducing government indebtedness itself is critically dependent upon maintaining economic growth i.e. ensuring that the GDP in the debt/GDP ratio grows at a healthy rate. In the fiat currency era (post 1945), one solution has usually been preferred to all others – the enforcement of prolonged periods of low or even negative real interest rates. In an excellent paper, Carmen Reinhart and Belen Sbrancia have analysed the role of “financial repression” in engineering negative real interest rates and reducing real government debt burdens between 1945 and 1980. Given the similarity of our current problems to the post-WW2 situation, it is no coincidence that a reduction in real rates has been a key component of central banks’ response to the crisis.

As Paul Krugman notes, the textbook monetary policy response to a liquidity trap requires that central banks “credibly promise to be irresponsible…to commit to creating or allowing higher inflation…so as to get negative real interest rates”. In the context of the current crisis, the central bank response has involved two distinct phases. In the first phase of the crisis, the priority is to prevent a deflationary collapse. Short of untested schemes that try to enforce negative nominal rates, deflation is inconsistent with a reduced real interest rate. In trying to mitigate the collapse, short rates were rapidly reduced to near-zero levels but equally critically, a panoply of “liquidity” programs were introduced to refinance bank balance sheets and prevent a collapse in shadow money supply. It is fair to critique the expansion of the Fed balance sheet for the backdoor bailout and resulting incentive problems it engenders in the financial sector. But in purely monetary terms, the exercise simply brings hitherto privately funded assets into the publicly funded domain.

Even after the deflationary collapse had been averted, simply holding short rates at zero and even a promise to hold rates at near-zero levels may be insufficient to reduce real rates sufficiently at the long end of the treasury curve. The market may simply not believe that the central bank is being credible when it promises to be “irresponsible”. Therefore the focus shifts to reducing the interest rates on longer-dated government bonds or even chosen risky assets via direct market purchases – MBS in the case of QE1 but there is no reason why even corporate bonds and equities could not be used for this purpose. If a fiat-currency issuing central bank does not care about inflation, it can enforce any chosen nominal rate at any maturity on the risk-free yield curve. Of course, in reality, central banks do care about inflation and therefore, instead of phrasing QE as a binding yield target, central banks limit themselves by the quantity of long-term bonds bought. As Perry Mehrling notes, QE2 is most similar to war finance and differs only in the choice of a quantity rather than a yield target. During WW2 the Fed essentially fixed the price of the entire government bond yield curve. Perry Mehrling describes it well in his excellent book“Throughout the war, the interest rate on Treasury debt was fixed at 3/8 percent for three-month bills and between 2 and 2½ percent for long-term bonds, and it was the job of the Fed to support these prices by offering two-way convertibility into cash…it was not until the Fed-Treasury Accord of March 1951 that the Fed was released from its wartime responsibility to peg the price of government debt.” The Fed-Treasury accord in 1951 that signalled the end of this phase was a consequence of an outbreak of inflation brought upon by the Korean War.

Arbitrage and Negative Real Rates

The textbook arbitrage response to ex-ante negative real rates is to buy and store the goods comprising one’s future consumption basket. In the real world, this is often not a realistic option and negative real rates can prevail for significant periods of time. This is especially true if inflation only exceeds risk-free rates by small amounts. Maintaining risk-free rates at low levels while running double-digit inflation levels risks demonetisation and hyperinflation but a prolonged period of small negative real rates may achieve the dual objective of growth and reduced indebtedness without at any point running a significant risk of demonetisation. So long as the central bank’s “pocket picking” is not too aggressive, the risk of demonetisation is slim.

As Reinhart and Sbrancia note, the option of enforcing negative real rates was available in the post-1945 environment only because “debts were predominantly domestic and denominated in domestic currencies.” Therefore although the US and Britain may try to follow the same policy again, it is clear that this option is not available to the peripheral economies in the Eurozone. Reinhart and Sbrancia argue that “inflation is most effective in liquidating government debts (or debts in general), when interest rates are not able to respond to the rise in inflation and in inflation expectations. This disconnect between nominal interest rates and inflation can occur if: (i) the setting is one where interest rates are either administered or predetermined (via financial repression, as described); (ii) all government debts are fixed- rate and long maturities and the government has no new financing needs (even if there is no financial repression the long maturities avoid rising interest costs that would otherwise prevail if short maturity debts needed to be rolled over); and (iii) all (or nearly all) debt is liquidated in one “surprise” inflation spike.” Condition (ii) is not satisfied in either the US or Europe whereas attempting to liquidate debt with one surprise inflation spike risks losing the credibility that central banks have fought so hard to acquire. Which leaves only option (i).

But even if investors cannot store their future consumption basket, could they simply not move into commodities or currencies with higher real rates of return? As James Hamilton notes, “there’s an incentive to buy and hold those goods that are storable…..episodes of negative real interest rates have usually been associated with rapidly rising commodity prices.” But the investment implications of negative real rates regimes are not quite so straightforward.

Implications for Financial Markets and Investment Strategies

In Reinhart and Sbrancia’s words, “inflation is most effective in liquidating government debts when interest rates are not able to respond to the rise in inflation and in inflation expectations.” If interest rates track the rise in inflation and real rates are positive, then a risk-averse investor simply needs to be invested in short-duration bonds (e.g. floating rate bonds) to preserve his purchasing power. In countries such as Australia, floating-rate bonds and short-duration bonds may preserve purchasing power in the same manner that inflation linkers can. But this does not hold for a countries such as the United States or the United Kingdom where real rates at the short-end are negative. Ex-ante negative real interest rates ensure that there is no “risk-free” asset in the market that can preserve one’s purchasing power. As Bill Gross notes: “bond prices don’t necessarily have to go down for savers to get skunked during a process of debt liquidation.” The logical response is to move to real assets or, as Bill Gross suggests, “developing/emerging market debt at higher yields denominated in non-dollar currencies” with a positive real interest rate. But as always, there are no free lunches.

Let’s assume that the market expects no “real rate suppression” to start with and the Fed surprises the market with an announcement that it intends to suppress the rate to the extent of 20% over the next decade. Assuming that Australian and Brazilian monetary and fiscal policy expectation remains unchanged by this announcement, the market should immediately revalue the Australian Dollar (AUD) and the Brazilian Real (BRL) upwards by 20%, a revaluation that it will give back over the next decade. Anyone who invests in either currency afterwards will not earn a superior return to what is available to him in USD. This idealised example makes many assumptions e.g. currency parity, ignores risk premiums and abstracts away from uncertainty. But the point that I am trying to make is simply this: Once real rate suppression has commenced, all asset prices will necessarily adjust to reflect the expected amount of suppression. Even a cursory look at the extent of recent appreciation in AUD or BRL tells us that much of this adjustment may have already taken place. In other words, there is no free lunch in moving away from USD to any other asset – an investment in real assets or foreign currency bonds only makes sense if one believes that the actual extent of suppression will exceed the current estimate.

Risk premiums will not change the above analysis in any meaningful manner. The idea that one can earn higher returns simply by turning up a “risk” dial is tenuous at the best of times but in the absence of a truly risk-free asset that preserves purchasing power, the very idea of a “risk premium” is meaningless. In the language of Kahneman and Tversky, it is the category boundary between certainty and uncertainty that matters most to an investor.

But the key difference between the above idealised example and the real world is the uncertainty about the extent and the pace of real rate suppression that a central bank will follow through with. The critical source of this uncertainty is the inflation and employment target that guides the central bank. The central bank may change its plans midway for a variety of reasons – a spike in inflation may put pressure on it to hike rates even if growth remains sluggish, a revival in real GDP growth may also allow it to unwind the program early. Even worse, inflation may slip below target despite the CB’s best efforts to stimulate investment and consumption demand i.e. the Japan scenario.

The expectation and distribution of real rate suppression influences the valuation of every asset price and the changes in this expectation and distribution become a significant source of market volatility across asset classes. What is also clear that for many real assets and foreign currency bonds, the present scenario where the economy muddles through without falling into either the Japan scenario or managing a strong recovery is the “best of all worlds”. To put it in the language of derivatives, if we define the amount of “real rate suppression” as the risk variable, then many real assets represent a “short volatility” trade. Obviously, this does not take into account the sensitivity of some of these assets to the economic conditions but this does not make it irrelevant even for assets such as US equities. The expected valuation uplift in equities from a strong economy may easily be at least partially negated by the reduced expectation of real rate suppression. This also illustrates how a jobless recovery that doesn’t turn into the Japan scenario is the ideal environment for equities. So long as monetary policy is guided by the level of employment, GDP growth without a pickup in employment maximises the expectation of rate suppression and by extension, the valuation of equity markets.

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Written by Ashwin Parameswaran

May 10th, 2011 at 6:28 am

Critical Transitions in Markets and Macroeconomic Systems

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This post is the first in a series that takes an ecological and dynamic approach to analysing market/macroeconomic regimes and transitions between these regimes.

Normal, Pre-Crisis and Crisis Regimes

In a post on market crises, Rick Bookstaber identified three regimes that any model of the market must represent (normal, pre-crisis and crisis) and analysed the statistical properties (volatility,correlation etc) of each of these regimes. The framework below however characterises each regime by the varying combinations of positive and negative feedback processes and the variations and regime shifts are determined by the adaptive and evolutionary processes operating within the system.

1. Normal regimes are resilient regimes. They are characterised by a balanced and diverse mix of positive and negative feedback processes. For every momentum trader who bets on the continuation of a trend, there is a contrarian who bets the other way.

2. Pre-crisis regimes are characterised by an increasing dominance of positive feedback processes. An unusually high degree of stability or a persistent trend progressively weeds out negative feedback processes from the system thus leaving it vulnerable to collapse even as a result of disturbances that it could easily absorb in its previously resilient normal state. Such regimes can arise from bubbles but this is not necessary. Pre-crisis only implies that a regime change into the crisis regime is increasingly likely – in ecological terms, the pre-crisis regime is fragile and has suffered a significant loss of resilience.

3. Crisis regimes are essentially transitional  – the disturbance has occurred and the positive feedback processes that dominated the previous regime have now reversed direction. However, the final destination of this transition is uncertain – if the system is left alone, it will undergo a discontinuous transition to a normal regime. However, if sufficient external stabilisation pressures are exerted upon the system, it may revert to the pre-crisis regime or even stay in the crisis regime for a longer period. It’s worth noting that I define a normal regime only by its resilience and not by its desirability – even a state of civilizational collapse can be incredibly resilient.

“Critical Transitions” from the Pre-Crisis to the Crisis Regime

In fragile systems even a minor disturbance can trigger a discontinuous move to an alternative regime – Marten Scheffer refers to such moves as “critical transitions”. Figures a,b,c and d below represent a continuum of ways in which the system can react to changing external conditions (ref Scheffer et al) . Although I will frequently refer to “equilibria” and “states” in the discussion below, these are better described as “attractors” and “regimes” given the dynamic nature of the system – the static terminology is merely a simplification.

In Figure a, the system state reacts smoothly to perturbations – for example, a large external change will trigger a large move in the state of the system. The dotted arrows denote the direction in which the system moves when it is not on the curve i.e. in equilibrium.  Any move away from equilibrium triggers forces that bring it back to the curve. In Figure b, the transition is non-linear and a small perturbation can trigger a regime shift – however a reversal of conditions of an equally small magnitude can reverse the regime shift. Clearly, such a system does not satisfactorily explain our current economic predicament where monetary and fiscal intervention far in excess of the initial sub-prime shock have failed to bring the system back to its previous state.

Figure c however may be a more accurate description of the current state of the economy and the market – for a certain range of conditions, there exist two alternative stable states separated by an unstable equilibrium (marked by the dotted line). As the dotted arrows indicate, movement away from the unstable equilibrium can carry the system to either of the two alternative stable states. Figure d illustrates how a small perturbation past the point F2 triggers a “catastrophic” transition from the upper branch to the lower branch – moreover, unless conditions are reversed all the way back to the point F1, the system will not revert back to the upper branch stable state. The system therefore exhibits “hysteresis” – i.e. the path matters. The forward and backward switches occur at different points F2 and F1 respectively, which implies that reversing such transitions is not easy. A comprehensive discussion of the conditions that will determine the extent of hysteresis is beyond the scope of this post – however it is worth mentioning that cognitive and organisational rigidity in the absence of sufficient diversity is a sufficient condition for hysteresis in the macro-system.

Before I apply the above framework to some events in the market, it is worth clarifying how the states in Figure d correspond to those chosen by Rick Bookstaber. The “normal” regime refers to the parts of the upper and lower branch stable states that are far from the points F1 and F2 i.e. the system is resilient to a change in external conditions. As I mentioned earlier, normal does not equate to desirable – the lower branch could be a state of collapse. If we designate the upper branch as a desirable normal state and the lower branch as an undesirable one, then the zone close to point F2 on the upper branch is the pre-crisis regime. The crisis regime is the short catastrophic transition from F2 to the lower branch if the system is left alone. If forces external to the system are applied to prevent a transition to the lower branch, then the system could either revert back to the upper branch or even stay in the crisis regime on the dotted line unstable equilibrium for a longer period.

The Magnetar Trade revisited

In an earlier post, I analysed how the infamous Magnetar Trade could be explained with a framework that incorporates catastrophic transitions between alternative stable states. As I noted: “The Magnetar trade would pay off in two scenarios – if there were no defaults in any of their CDOs, or if there were so many defaults that the tranches that they were short also defaulted alongwith the equity tranche. The trade would likely lose money if there were limited defaults in all the CDOs and the senior tranches did not default. Essentially, the trade was attractive if one believed that this intermediate scenario was improbable…Intermediate scenarios are unlikely when the system is characterised by multiple stable states and catastrophic transitions between these states. In adaptive systems such as ecosystems or macroeconomies, such transitions are most likely when the system is fragile and in a state of low resilience. The system tends to be dominated by positive feedback processes that amplify the impact of small perturbations, with no negative feedback processes present that can arrest this snowballing effect.”

In the language of critical transitions, Magnetar calculated that the real estate and MBS markets were in a fragile pre-crisis state and no intervention would prevent the rapid critical transition from F2 to the lower branch.

“Schizophrenic” Markets and the Long Crisis

Recently, many commentators have noted the apparently schizophrenic nature of the markets, turning from risk-on to risk-off at the drop of a hat. For example, John Kemp argues that the markets are “trapped between euphoria and despair” and notes the U-shaped distribution of Bank of England’s inflation forecasts (table 5.13). Although at first glance this sort of behaviour seems irrational, it may not be – As PIMCO’s Richard Clarida notes: “we are in a world in which average outcomes – for growth, inflation, corporate and sovereign defaults, and the investment returns driven by these outcomes – will matter less and less for investors and policymakers. This is because we are in a New Normal world in which the distribution of outcomes is flatter and the tails are fatter. As such, the mean of the distribution becomes an observation that is very rarely realized”

Richard Clarida’s New Normal is analogous to the crisis regime (the dotted line unstable equilibrium in Figures c and d). Any movement in either direction is self-fulfilling and leads to either a much stronger economy or a much weaker economy. So why is the current crisis regime such a long one? As I mentioned earlier, external stabilisation (in this case monetary and fiscal policy) can keep the system from collapsing down to the lower branch normal regime – the “schizophrenia” only indicates that the market may make a decisive break to a stable state sooner rather than later.

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Written by Ashwin Parameswaran

July 29th, 2010 at 3:27 am

Heuristics and Robustness in Asset Allocation: The 1/N Rule, “Hard” Constraints and Fractional Kelly Strategies

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Harry Markowitz received the Nobel Prize in Economics in 1990 for his work on mean-variance optimisation that provided the foundations for Modern Portfolio Theory (MPT). Yet as Gerd Gigerenzer notes, when it came to investing his own money, Markowitz relied on a simple heuristic, the “1/N Rule” which simply allocates equally across all N funds under consideration. At first glance, this may seem to be an incredibly irrational strategy. Yet, there is compelling empirical evidence backing even such a simple heuristic as the 1/N Rule. Gigerenzer points to a study conducted by DeMiguel, Garlappi and Uppal (DMU) which after comparing many asset-allocation strategies including Markowitz mean-variance optimisation concludes that “there is no single model that consistently delivers a Sharpe ratio or a CEQ return that is higher than that of the 1/ N portfolio, which also has a very low turnover.”

Before exploring exactly what the DMU study and Gigerenzer’s work implies, it is worth emphasizing what it does not imply. First, as both DMU and Gigerenzer stress, the purpose of this post is not to argue for the superiority of the 1/N Rule over all other asset-allocation strategies. The aim is just to illustrate how simple heuristics can outperform apparently complex optimisation strategies under certain circumstances. Second, the 1/N Rule does not apply when allocating across securities with excessive idiosyncratic risk e.g. single stocks. In the DMU study for example, the N assets are equity portfolios constructed on the basis of industry classification, countries, firm characteristics etc.

So in what circumstances does the 1/N Rule outperform? Gigerenzer provides a few answers here as do DMU in the above-mentioned study but in my opinion, all of them come down to “the predictive uncertainty of the problem“. When faced with significant irreducible uncertainty, the robustness of the approach is more relevant to its future performance than its optimality. As Gigerenzer notes, this is not about computational intractability – indeed, a more uncertain environment requires a simpler approach, not a more complex one. In his words: “The optimization models performed better than the simple heuristic in data fitting but worse in predicting the future.”

Again, it’s worth reiterating that both studies do not imply that we should abandon all attempts at asset allocation – the DMU study essentially evaluates the 1/N Rule and all other strategies based on their risk-adjusted returns as defined under MPT i.e. by their Sharpe Ratio. Given that most active asset management implies a certain absence of faith in the canonical assumptions underlying MPT, some strategies could outperform if evaluated differently. Nevertheless, the fundamental conclusion regarding the importance of a robust approach holds and a robust asset allocation can be achieved in other ways. For example, when allocating across 20 asset categories, any preferred asset-allocation algorithm could be used with a constraint that the maximum allocation to any category cannot exceed 10%. Such “hard limits” are commonly used by fund managers and although they may not have any justifying rationale under MPT, this does not mean that they are “irrational”.

The need to increase robustness over optimisation when faced with uncertainty is also one of the reasons why the Kelly Criterion is so often implemented in practise as a “Fractional Kelly” strategy. The Kelly Criterion is used to determine the optimal size of sequential bets/investments that maximises the expected growth rate of the portfolio. It depends crucially upon the estimate of the “edge” that the trader possesses. In an uncertain environment, this estimate is less reliable and as Ed Thorp explains here, the edge will most likely be overestimated. In Ed Thorp’s words: “Estimates….in the stock market have many uncertainties and, in cases of forecast excess return, are more likely to be too high than too low. The tendency is to regress towards the mean….The economic situation can change for companies, industries, or the economy as a whole. Systems that worked may be partly or entirely based on data mining….Systems that do work attract capital, which tends to push exceptional [edge] down towards average values.”

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Written by Ashwin Parameswaran

July 8th, 2010 at 5:31 am