That’s a rough estimate of the volume of outstanding contracts in financial derivatives, mainly interest swaps (some year-old and incomplete data here totals $175 trillion). As the name implies, these are usually matched, so that the actual net exposure of any party is a tiny fraction of the gross. But if the counterparty on one side of the swap should default, things could get very nasty. And, given the volume, default on a small proportion of the contracts would overwhelm the resources of the world’s central banks. To get an idea of magnitudes, US GDP is about $11 trillion or 5.5 per cent of outstanding contracts. When Long Term Credit Management went bust in 1998, threatening the stability of the world’s financial system, its gross position totalled $1.25 trillion, or about 0.6 per cent of the amount outstanding today.
Of course, the central bankers and prudential regulators have everything under control, and have simulated all the possible things that can go wrong. As for experimental tests of the stability of the system, we haven’t really had one yet, apart from LTCM. The last time the US financial system came under any real stress was the 1990 recession (or maybe the 1987 crash) at which time the volume of derivatives was maybe $1 trillion.
Still, as Eeyore said in a rather similar situation, “That’s what makes it so terribly interesting. Not really knowing until afterwards”.