HSBC is poised to reveal a further $3.5-4 billion (£1.8-2 billion) in bad-debt charges from its American business, as homeowners there continue to fall behind with mortgage payments.

First-quarter results from the bank’s American business are expected to reveal it has recorded a loss of at least $1 billion as a result of the charges.

HSBC has already written off more than $14 billion in bad debts from the American business since the fourth quarter of 2006 – more than it paid to acquire the Household International business five years ago.

A group trading statement due to be published alongside the American figures is also expected to show signs of rising bad debts among UK small-business customers.

Barclays is expected to use the recent Bank of England report to support its accounting methodologies. The Bank said many credit positions had been written down too far by the world’s biggest banks, and the true value was probably higher.

Analysts believe that RBS has taken excessive write-downs on some of its credit positions to aid its planned £12 billion rights issue, according to analysts. Some of the bank’s exposures to credit vehicles are valued in a way that suggests they will receive only two more income payments before the vehicles go bust.

Sources say many of RBS’s credit investments have yet to suffer defaults so the valuation is not realistic – it is enforced by the share-issue underwriters Merrill Lynch, Goldman Sachs and UBS.

It is understood that Barclays is still talking to a number of sovereign wealth funds and Asian banks about a share placing. However, growth in the bank’s Asian operations is expected to be strong enough to offset problems in America and elsewhere. Analysts still believe the bank can clock up profits of more than $20 billion in the current financial year.

The figures come as the markets prepare for another week of bad news from the British banking sector. Alliance & Leicester is expected to reveal further write-downs and warn of deteriorating profitability.

Barclays is expected to confound its critics once again, and stop short of raising additional capital. Banking sources believe the group will value a number of its sub-prime mortgage securities substantially higher than peers such as Royal Bank of Scotland and UBS.

Such a move could mean Barclays has to make write-downs of less than £1 billion – far less than the £5.5 billion that has been widely rumoured by some analysts.

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