America's dreaded sub-prime skeletons were again rattling stock markets on both sides of the Pond yesterday.

They will from time to time until there is a plausible reason to suppose that we know where most of the skeletons are.

Yesterday it was Citigroup's turn, with one analyst warning that this colossus of American banking may have to beef up its capital ratios by selling assets, cutting its dividend, or, heaven forfend, asking its shareholders for cash.

All the big American banks have had to come up with numbers for their subprime pain for the purposes of their quarterly results.

Most were less dreadful than first feared.

Then Merrill Lynch had to do it again - and lost its chief executive.

Well, if Merrill has second thoughts, how can we be so sure about the rest? Yesterday the spotlight fell on Citigroup. It will not be the last.

British banks, though don't report quarterly. So they have all kept stumm. They can wait till next year.

True, any listed company that runs into something "material" that alters what are regarded as "expectations" of its performance, is supposed to put its hands up and tell the world.

But what sort of expectations are realistic or sensible for a bank in times like these?

Do we realistically expect The Royal Bank of Scotland's Sir Fred Goodwin to find no wood lice at all as he lifts his newly bought stones at ABN Amro?

Does an ordinary, sceptical observer of banks suppose that whatever caused Barclays to accept help twice from the Bank of England in September has done its profits no particular harm?

Yesterday the stock market was in no mood to take much for granted.

American jitters about something the size of Citigroup are infectious, almost by definition.

British bank shares were already pricing in a fair bit of unpleasantness. You have been able to get a dividend yield of over six per cent on the Royal Bank for weeks.

Yet in real life Sir Fred would rather cut his throat (and yours) than cut his dividend - and everybody knows it.

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The name missing from the list of America's self-confessed loss-makers is mighty Goldman Sachs.

It is a partnership, so not obliged to tell anyone anything.

Still, its silence does reinforce a formidable reputation for getting things right.

Well, a few days ago, when everyone else was talking oil up to $100 and beyond, Goldman put out a note giving a target price of $80 a barrel citing grow-ing "downside risks".

David Jones at Montague Asset Managers in Stratford-on-Avon aired the mischievous thought that they may have sold the black stuff short and want to collect a quick profit.

Be that as it may, the oil price was jumping around yesterday - first up beyond $96, then back to $93.64 for a loss on the day.

If this tide is turning, no bad thing. If some hedge funds are caught, better still.

Yesterday Goldman's bears turned their eye to mining shares and the promising shake-out in copper and zinc prices - a long overdue and welcome development for real-life industry.