Monday, September 21, 2009

Lehman should not be allowed to fall



I am about to mark the anniversary of the financial meltdown. In September 2008 bankruptcy of Lehman Brothers freeze the global financial system for several weeks. But the fall of Lehman was not the cause of the crises but rather a late symptom of cracks in the financial system caused by very high leverage. Financial intermediaries naturally leverage their balance sheets. But Chart 1 point to a strong positive relationship between changes in leverage and the size in balance sheet size which suggest a high procyclical in the leverage process of financial intermediaries.


Chart 1 reproduced from Hyun Song Shin

In good times leverage and balance sheet size of financial intermediaries increase together when risks decrease measured (VaR). But when the loss distribution is exponential, the behavior of intermediaries conforms to the Value-at-Risk rule, in which exposure is adjusted to maintain a constant probability of default. In a system context, increased risk reduces the debt capacity of the financial system as a whole, giving rise to amplified de-leveraging by institutions through the chain of repo transactions. This process leads to a synchronized contraction of balance sheets which will cause stresses that show up somewhere in the system.



Chart 2 US Fedwired interbank payment network reproduced from K.Soramäki




In case of the financial networks it is crucial for its sustainability to know where the stresses may show up as its topology is highly disassortative. I.E.US FED payment system contains over 9500 participating banks but the core of the network with 66 banks accounts for 75% of the daily transactions. Distribution of the connections between participants in that network follows the power law distributions (few banks are hubs for thousands of others while thousands of banks in that network are only connected to few others).
The good news is that this type of network (scale-free network) is very resilient to accidental failure as random failure even large amount of banks is unlikely to freeze the whole system ( the random failure of banks will take only the small ones as they are much more plentiful than the hubs ).

The Achilles heel of the network is its dependence on hubs (large interconnected banks) . Recent research suggests that generally speaking, that the simultaneous collapse of only of 5-15% of all hubs can crash free scale network. Therefore the protecting the hubs of the system are essential for its functioning. Allowing Lehman to collapse which was a central hub in financial network was clearly against this rule and was a major and cost full mistake.

Conclusions are rather fairly simple:

1) Regulators/central banker should watch and limit the leverage in the financial system (not only target inflation)

2) core of the network should be protected at all cost but also should be subject of stricter regulations

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Tuesday, September 8, 2009

The Chinese equity bubble - UPDATE

Dieter Sornette and his team just released an updated version of its earlier paper on Chinese equity bubble. This version of the paper includes more details i.e. description of bubble detection tools etc. Link here

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Thursday, September 3, 2009

World stock market: approaching trend reversal?

Another interesting implementation of LPPL model has been just published today. Stanislaw Drozdz and Pawel Oswiencimka in short paper predict that core stocks indexes will face significant correction. A quote:

Based on our ”finance-prediction-oriented” methodology which involves such elements as log-periodic self-similarity, the universal preferred scaling factor 2, and allows a phenomenon of the ”super-bubble” we analyze the 2009 world stock market (here represented by the S&P500, Hang Seng and WIG) development. We identify elements that indicate the third decade of September 2009 as a time limit for the present bull market phase which is thus to be followed by a significant correction

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Sugar bubble ready to burst

Over the past few weeks, sugar has been on such upward spiral, hitting a 28-year high. Growing demand in Brazil for sugar to be turned into ethanol, coupled with a sharp fall in Indian and Brazilian production, have both sent sugar prices sky high. Many think that the supply shortfall will extend through 2010. Then from fundamental perspective valuation current sugar valuation may be correct as the supply fall short behind the demand. But to speak of supply and demand as if they were determined by forces that are independent of the market participant’s expectations is quite misleading.

It’s true the situation is not so clear cut in case of commodities where supply is largely dependent on production and demand on consumption. But the price that determines the amounts produced and consumed is not necessarily the present price. On the contrary, the market participants are more likely to be guided by future prices, either as expressed in future markets or as anticipated by themselves. In either case it is inappropriate to speak of independently given supply and demand curves because both curves incorporate expectations about future prices.

Those expectations may become self-referential which will lead to the positive feedback process (the higher the price or the price return in the recent past, the higher will be the price growth in the future). Positive feedbacks, when unchecked, can produce runaways which beyond a certain point become unsustainable ending in crash. In short LPPL models developed by Sornette aims, at detecting the transient phases where positive feedbacks operating on some markets or asset classes create local unsustainable price run-ups. The result of the analysis is summarized bellow in figure 1.



I analyzed sugar#11 future time series between September 2007 and September 3 2009. The y axis is logarithmically scaled so that the exponential function would appear as a straight line. LPPL fit exhibit upward curvature which is clear evidence that the prices were growing “super-exponentially”. The projected crash dates are September 5-15 .It must be noted that a good fit of the model to the data series is not a 100% certainty for a crash, but it clearly points at a bubble formation.

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Monday, July 13, 2009

The Chinese Equity Bubble: Ready to Burst (NOW)

D. Sornette et all just published interesting working paper on possibility of Chinese equity bubble to burst. A quote from summary:

Amid the current financial crisis, there has been one equity index beating all others: the Shanghai Composite. Our analysis of this main Chinese equity index shows clear signatures of a bubble build up and we go on to predict its most likely crash date: July 17-27, 2009 (20%/80% quantile confidence interval).

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Saturday, July 11, 2009

Larry Summers on EMH

In today’s Financial Times you can find an interesting interview with Larry Summers, director of the US president’s National Economic Council. A quote:


The chief intellectual casualty of the current crisis has been the “efficient markets” school – the theory, associated with such erstwhile laisser faire gurus as Alan Greenspan, that market participants are governed by rational expectations and markets are self-correcting. As an academic economist, Summers has studied the shortcomings of that approach but, working on Wall Street gave him, he says, a more visceral understanding of the “self-referential” character of markets: “Markets are concerned with the ultimate health of economies and the like but they’re equally or more concerned with what the likely judgments of other market participants in the short run are.”

I’m not quite sure whether Mr. Summers is aware that he is proposes to extend economists tool box with non-equilibrium models. Nevertheless it may indicate that non-equilibrium models are silently leaking into main stream of economics. Efficient Market Hypothesis (EMH)has been falsified many times but I hope that this time it will be replaced by hypothesis better explaining how the market works. I think that G.Soros Reflexivity idea or MIT Andrew Lo Adaptive Market Hypothesis are good candidates to replace EMH for good.

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Wednesday, July 8, 2009

Asset price misalignments and the role of money and credit

ECB just released working paper on the role of money and credit indicators for detecting asset prices misalignments. This is most likely the second ECB publication on early warning asset bubbles indicators this year. Conclusion are quite intuitive that monetary and credit developments may be very useful in predicting asset bubbles burst. I have no problem with that conclusion because positive feedback loop from credit to house prices and again to credit was behind surge of house prices (also in Eastern Europe). I think that that to reduce price to price feedback (to avoid superbubbles creation) central banks should be more focused on credit growth and also closely monitor interactions between collateral valuation (i.e. house prices) and banks willingness to lend.

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