When finance ministers from the Group of Seven nations gathered in Tokyo last weekend, the mood was distinctly gloomy. With credit stresses spreading, policymakers agreed that the financial outlook looked distinctly "uncertain".
One of the biggest - and most practical - concerns now revolves around a seemingly simple question: who is about to be hit next with subprime pain?
When it emerged a year ago that US subprime mortgage borrowers were defaulting on their loans, the US Federal Reserve initially estimated this could cause $50bn of losses.
It subsequently revised this up to $100bn-$150bn, and many investment banks then doubled that number.
However, at the weekend meeting in Tokyo, Peer Steinbrück, German finance minister, revealed that the G7 now thought subprime losses could reach $400bn - markedly more gloomy than anything that has emanated from official quarters.
But if that is striking, what is doubly thought provoking is that Western investment banks have hitherto confessed to "only" $120bn-odd of losses. The question worrying G7 leaders is where the remaining $280bn of problems may lie? Or as one senior policymaker confessed: "What everyone is trying to work out is where the rest of the bodies are."
A full forensic analysis is unlikely to emerge soon. That is partly because of a time lag issue: many of the potential $400bn of losses have not yet occurred, let alone worked their way through the system - or, more specifically, through the complex chain of financial instruments linked to the subprime world.
Another issue complicating the debate is the sheer variety of accounting standards being used around the world - and across the financial industry - in relation to subprime.
In recent weeks Wall Street banks have come under severe auditor pressure to mark their books to market, and thus reveal losses. But regulators admit that it remains unclear - even now - whether these banks are using similar pricing standards.
Outside Wall Street, suspicions are rife that other institutions are still concealing losses, partly because they have less pressure to use mark to market accounting. In particular, there is now rising concern about so-called "buyside" institutions, or entities that have been purchasing mortgage-linked securities in recent years, rather than selling them on.
"The problems are moving from the sellside to the buyside - that is where the losses are still to be recognised," one structured finance expert told a conference in London last week.
Small and medium-sized European banks, for example, are attracting particular scrutiny from investors since some of these have been big buyers of structured products.
Although European banks, as a whole, have not revealed as much subprime pain as their US counterparts, Mario Draghi, Bank of Italy governor, stressed last weekend that it was still too early to draw firm conclusions - or comfort - from this discrepancy.
Some regulators and investors are also looking closely at financial institutions in Asia, particularly Taiwan and Korea, which have also been enthusiastic purchasers of structured products in recent years.
Insurance companies are attracting close scrutiny, since these have also had a hefty presence in structured credit this decade and also tend to eschew aggressive mark to market accounting practices. Indeed, AIG's share price tumbled yesterday amid such concerns.
As long as this striking accounting variety remains, the sense of endemic unease - or outright distrust - is likely to remain. This terrible $280bn mystery, in other words, may have a great deal further to run.
