Today's release of the 2013 edition of the Global Shadow Banking Monitoring Report [7]by the Financial Stability Board doesn't contain anything that frequent readers of this site don't know already on a topic we have covered since 2009. It does however have a notable sidebar which explains the magic of "(un)fractional repo banking" - a topic made popular in late 2011 [8]following the collapse of MF Global - when it was revealed that as part of the Primary Dealer's operating model, a core part of the business was participating in UK-based repo chains in which the collateral could be recycled effectively without limit and without a haircut, affording Jon Corzine's organization virtually unlimited leverage starting with a tiny initial margin.
Naturally, any product that can allow participants infinite leverage is something that all "sophisticated" market participants not only know about, but abuse on a regular basis. The fact that this "unfractional repo banking" is at the heart of the unregulated $71.2 trillion shadow banking system, the less the general public knows about it the better.
Which is why we were happy that the FSB was kind enough to explain in two short paragraphs and one even simpler chart, just how the aggregate leverage for the participants in even the simplest repo chain promptly becomes exponential, far above the "sum of the parts", and approaches infinity in virtually no time.
From the FSB:
As a simple illustration of the way in which repo transactions can combine to produce adverse effects on the system that can be larger than the sum of their parts, suppose that investor A borrows cash for a short period of time from investor B and posts securities as collateral. Investor A could use some of that cash to purchase additional securities, post those as further collateral with investor B to receive more cash, and so on multiple times. The result of this series of ‘leveraging transactions’ is that investor A ends up posting more collateral in total with investor B than they initially owned outright. Consequently, small changes in the value of those securities have a larger effect on the resilience of both counterparties. In turn, investor B could undertake a similar series of financing transactions with investor C, re-using the collateral it has taken from investor A, and so on.
Exhibit A2-5 mechanically traces out the aggregate leverage that can arise in this example. Even with relatively conservative assumptions, some configurations of repo transactions boost aggregate leverage alongside the stock of money-like liabilities and interconnectedness in ways that might materially increase systemic risk. For example, even with a relatively high collateral haircut of 10%, a three-investor chain can achieve a leverage multiplier of roughly 2-4, which is in the same ball park as the financial leverage of the hedge fund sector globally. It is therefore imperative from a risk assessment perspective that adequate data are available. Trade repositories, as proposed by FSB Workstream 5, could be very helpful in this regard.
[9]
So... three participants result in 4x leverage; four: in roughly 6x, and so on. Of course, these are conservative estimates: in the real, collateral-strapped world, the amount of collateral reuse, and thus the number of participants is orders of magnitude higher. Which means that after just a few turns of rehypothecation, leverage approaches infinity. Needless to say, with infinite leverage, even the tiniest decline in asset values would result in a full wipe out of one collateral chain member, which then spreads like contagion, and destroys everyone else who has reused that particular collateral.
All of this, incidentally, explains why down days are now prohibited. Because with every risk increase, there is an additional turn of collateral re-use, and even more participants for whom the Mutual Assured Destruction of complete obliteration should the weakest link implode, becomes all too real.
That, in a nutshell, are the mechanics. As to the common sense implications of having an unregulated funding market which explicitly allows infinite leverage, we doubt we have to explain those to the non-Econ PhD readers out there.
Source [10]