Eurozone woes are US woes
A different perspective on the risks the world faces from the financial woes of Greece, Ireland and Portugal is provided by a new class of statistics published today by the Bank for International Settlements (BIS), the central bankers' central bank.
What it shows is that US banks are collectively second or third most exposed to the woes of Greece, Portugal and Ireland, through what the BIS calls their "potential exposure" to these countries.
This new visibility for the big bets US banks have made on the eurozone's most overstretched economies could prove controversial in Washington - coming so soon after these banks were bailed out by US taxpayers.
The stats show that there is some considerable alignment of eurozone and US interests in preventing a Greek default - though I can see circumstances in which the US and the eurozone would be at loggerheads over some eurozone leaders' hope that creditors to Greece would be encouraged (though not forced) to roll over their loans to Greece, as those loans fell due for payment.
US banks in the hock
The scale of how much money American banks have at risk in the eurozone comes from a new BIS table of the actual and potential exposure of banks to most economies via cross-border loans and financial transactions. It's the detail on potential exposures that is illuminating.
For example, it shows that the potential exposure of US banks to Greece is $34bn (£20.7bn, 23.2bn euro) - which is as much as the actual exposure of German banks to Greece.
If you add together these actual and potential exposures, French banks have most at risk in Greece, with $65bn of exposure. Then - to my amazement - comes the US, with $41bn of actual and potential exposure, or $1bn more than the exposure of German banks.
Actual and potential exposure of UK banks is "just' $19bn.
So what are these "potential" exposures? In the case of American banks' $34bn exposure to Greece, $33bn is described as "guarantees".
Which doesn't tell us a great deal. The talk is that most of these guarantees are for credit derivatives, or insurance against Greece not paying its debts - but I can't be sure that's so.
Greece, then Portugal, and then...
Either way, America's banks would seem to have a good deal to lose if Greece were to go kaput.
Also, the BIS stats show that the potential exposure of US banks to Portugal is a quite remarkable $41bn, and their total exposure to Portugal is $46bn.
Only Spanish banks, with $106bn of actual and potential exposure to Portugal, and German banks, with $50bn of actual and potential loans to Portugal, have more money at risk.
For Ireland, US banks' potential exposure is $54bn and their actual exposure is $51bn, or $105bn in total - which puts them in third place behind the UK (with $194bn of Irish exposure) and Germany (with $158bn of exposure).
And in the case of Spain, the actual and potential exposure of US banks is a knee-trembling $179bn - so there is a powerful American interest in the eurozone's rot stopping with Greece, Ireland and Portugal.
All this helps to explain why the US administration has been taking a close personal interest in the eurozone's troubles - and why the US has been making it clear that it would prefer there weren't a "credit event" that could be described as a Greek default.
US bail-out for creditors?
What's unclear is whether the idea being floated by eurozone officials that existing creditors of Greece should be encouraged to re-lend to Greece, when their debts mature, would count as a default.
Under consideration is a stark warning to Greece's creditors that they'll only get their money back as it falls due if they immediately lend it back to Greece.
Now it is conceivable that creditors would see such pressure to extend the maturity of a loan as a de facto default, even if the rollover were not mandatory: it would be a demonstration that the eurozone and IMF weren't prepared to provide all the liquidity needed by Greece.
So the semi-voluntary provision of new loans by existing creditors might not prove the painless solution its proponents believe it to be.
For US banks in particular, there's an important question whether this encouraged rollover of loans would oblige them to pay out under the credit derivative contracts they may have written to insure the debt.
In other words, US banks could find themselves bailing out Greece's European bank creditors - and that might not be universally popular in Washington, so soon after those US banks were rescued by US taxpayers.