Is this something to really worry about? Only if you understand it and how many people truly do?

Zero Hedge a website that I look at but rarely fully comprehend has another scary article up, see if you understand it completely, or even partially. Here are a long extract from an even longer article:

'While the dominant topic of conversation when discussing margin hikes (or reductions) usually reverts to silver, ES (stocks) and TEN (bonds), what everyone so far is ignoring is the far more critical topic of real margin risk, in the form of roughly $600 trillion in OTC derivatives. The issue is that while the silver market (for example) is tiny by comparison, it is easy to be pushed around, and thus exchanges can easily represent the illusion that they are in control of counterparty risk (after all, that was the whole point of the recent CME essay on why they hiked silver margins 5 times in a row). Nothing could be further from the truth: where exchanges are truly at risk is when it comes to mitigating the threat of counterparty default for participants in a market that is millions of times bigger than the silver market: the interest rate and credit default swap markets. As part of Dodd-Frank, by the end of 2012, all standardised over-the-counter derivatives will have to be cleared through central counterparties. Yet currently, central clearing covers about half of $400 trillion in interest rate swaps, 20-30 percent of the $2.5 trillion in commodities derivatives, and about 10 percent of $30 trillion in credit default swaps. In other words, over the next year and a half exchanges need to onboard over $200 trillion notional in various products, and in doing so, counterparites, better known as the G14 (or Group of 14 dealers that dominate derivatives trading including Bank of America-Merrill Lynch, Barclays Capital, BNP Paribas, Citi, Credit Suisse, Deutsche Bank, Goldman Sachs, HSBC, JP Morgan, Morgan Stanley, RBS, Societe Generale, UBS and Wells Fargo Bank) will soon need to post billions in initial margin, and as a brand new BIS report indicates, will likely need significant extra cash to be in compliance with regulatory requirements. Not only that, but once trading on an exchange, the G14 "could face a cash shortfall in very volatile markets when daily margins are increased, triggering demands for several billions of dollars to be paid within a day." Per the BIS "These margin calls could represent as much as 13 percent of a G14 dealer's current holdings of cash and cash equivalents in the case of interest rate swaps." Below we summarize the key findings of a just released discussion by the BIS on the "Expansion of central clearing" and also present a parallel report just released by BNY ConvergEx' Nicholas Colas who independetly has been having "bad dreams" about the possibility of what the transfer to an exchange would mean in terms of collateral posting (read bank cash payouts) and overall market stability, and why a multi-trillion margin call could result in the biggest buying spree in US Treasurys... Ever. 
First, for those who are unfamiliar, here is what happens when an exchange (or a Central Counterparties) proceeds to trade OTC derivatives with any given counterparty (from the BIS):

CCPs typically rely on four different controls to manage their counterparty risk: participation constraints, initial margins, variation margins and non-margin collateral.

A first set of measures are participation constraints, which aim to prevent CCPs from dealing with counterparties that have unacceptably high probabilities of default.

The second line of defense is initial margins in the form of cash or highly liquid securities collected from counterparties. These are designed to cover most possible losses in case of default of a counterparty. More specifically, initial margins are meant to cover possible losses between the time of default of a counterparty,8 at which point the CCP would inherit its positions, and the closeout of these positions through selling or hedging. On this basis, our hypothetical CCP sets initial margins to cover 99.5% of expected possible losses that could arise over a five-day period. CCPs usually accept cash or high-quality liquid securities, such as government bonds, as initial margin collateral.

As the market values of counterparties’ portfolios fluctuate, CCPs collect variation margins, the third set of controls. Counterparties whose  portfolios have lost market value must pay variation margins equal to the size of the loss since the previous valuation. The CCP typically passes on the variation margins it collects to the participants whose portfolios gained in value. Thus, the exchange of variation margins compensates participants for realised profits/losses associated with past price movements while initial margins protect the CCP against potential future exposures. Variation margins, typically paid in cash, are usually collected on a daily basis, although more than one intraday payment may be requested if prices are unusually volatile.

Finally, if a counterparty defaults and price movements generate losses in excess of the defaulter’s initial margin before its portfolio can be closed out, then the CCP would have to rely on a number of additional (“non-margin”) resources to absorb the residual loss. The first of these is a default  fund. All members of the CCP post collateral to this fund. The defaulting dealer’s contribution is used first, but after this other members would incur losses. The default fund contribution of the defaulting dealer would be mutualised among the non-defaulting dealers according to a predetermined formula. Some additional buffers may then be available, such as a third-party guarantee or additional calls on the capital of CCP members.

Otherwise, the final buffer against default losses is the equity of the CCP. In order to calculate initial and variation margins, CCPs rely on timely price data that give an accurate indication of liquidation values. Clearing OTC derivatives that could become unpredictably illiquid in a closeout scenario could impose an unacceptable risk on the CCP.

Table 1 summarises the risk management practices of SwapClear, ICE Trust US and ICE Clear Europe, which are currently the main central clearers of IRS and CDS.

The gist of the BIS paper focuses not so much on the inboarding costs and concerns of migrating hundreds of trillions of products to CCP - a topic evaluated much more in depth by Nick Colas - the BIS does instead look at a hypothetical example of what may happen in the case of a "risk flaring" episode, and how much variation margin G14's may need to post:

As shown in the left-hand panels of Graph 2, estimated initial margins can vary significantly with prevailing levels of market volatility, especially for CDS. The upper left-hand panel shows, for example, that Dealer 7 would need to post $2.1 billion of collateral to clear its hypothetical IRS portfolio in an environment of low market volatility, similar to that prevailing before the recent financial crisis. This would grow by around 50%, to $3.2 billion, if volatility increased to the “medium” level seen early in the crisis, just before the rescue of Bear Stearns. And it would grow by around 150%, to $5.3 billion, if volatility increased to the “high” level seen at the peak of the crisis, amidst the negative market reaction to the US Troubled Asset Relief Program (TARP) and before government recapitalisation of banks began in the United Kingdom. In comparison, the bottom left-hand panel shows that initial margin requirements for the hypothetical CDS portfolio of Dealer 7 would increase by around 160% or 325% from $0.6 billion if the prevailing level of market volatility increased from low to medium or high. The total initial margins that the CCP requires clearing members to post are $33 billion (low), $70 billion (medium) and $105 billion (high) for IRS and $6 billion (low), $20 billion (medium) and $35 billion (high) for CDS.

Nevertheless, it seems unlikely that G14 dealers would have much difficulty finding sufficient collateral to post as initial margin. The diamonds in the left-hand panels show collateral requirements relative to dealers’ unencumbered assets, with different colours again representing different levels of market volatility. Even the requirements based on high levels of volatility do not exceed 3% of the unencumbered assets of any dealer for which it was possible to estimate this figure. Although many unencumbered assets held by dealers do not presently qualify as acceptable collateral for initial  margins, some of these could be swapped for assets that do qualify.

By contrast, dealers may need to increase the liquidity of their assets as central clearing is extended. The centre panels of Graph 2 show similar patterns in potential variation margin calls as prevailing levels of market volatility change. In the worst case, variation margins could be several  billions of dollars, which would have to be paid in cash within a day. These margin calls could represent as much as 13% of a G14 dealer’s current  holdings of cash and cash equivalents in the case of IRS. A five-day sequence of large variation margin calls that could be expected with a probability of one in 200 would equate to around 28% of current cash and cash equivalents in the worst case.

These results also have direct implications for the liquidity provisions of CCPs, as they would have to pay variation margins in the case of default of  a clearing member. Access to central bank funds in distressed circumstances would help to ensure that CCPs could make substantial variation  margin payments in a timely manner.

...

With a probability of one in 10,000, non-margin resources at risk from the failure of one particular dealer, two particular dealers or any dealer with sufficiently adversely affected portfolios would respectively be 20%, 37% and 42% of total initial margins for IRS, and 36%, 46% and 65% of total initial margins for CDS. If prevailing levels of volatility were high, these figures would equate to $21 billion, $39 billion and $44 billion for IRS, and $13 billion, $16 billion and $23 billion for CDS. By comparison, the G14 dealers contributing to default funds had equity of around $1.5 trillion as of 30 June 2010.

Alas, the problem is that the bulk of this "equity" is, for lack of a better word, worthless, as it is based on such assets as intangibles, and MTM-locked up assets, whose true value is far, far lower than where banks carry these. And of course, the need to sell them would come precisely at a time when everyone else would be selling. Which means that in the event of a market lockup, there would be no one on the other side of the trade, meaning the entire CCP experiment would likely collapse spectacularly, as nowhere near enough cash is available.'

I am pretty sure that I should be worried, very  worried but I am not sure I could explain why!