HSBC yesterday said its profits are rising but its warning of a possible writedown of its US business and a faltering economy in the Far East left investors wary.

It was a day of surprises from some of the banks thought to have weathered the credit crunch best. Santander, the Spanish bank which has snapped up Alliance & Leicester and the deposit side of Bradford & Bingley in recent months, launched a 7.2bn (£5.9bn) rights issue. Clydesdale owner National Australia Bank first said it was raising A$2bn (£858m) in a share placement then upped it to some A$3bn.

Shares in HSBC fell 11p, or 1.5%, in the course of the day to 735.5p despite telling investors its third-quarter profits were up on a year ago as resili-ent earnings from Asia, South America and the Middle East offset rising US bad debts.

The bank said it was attracting business, particularly in UK mortgages and private banking, as some of its competitors coped with funding problems and raised capital.

HSBC chairman Stephen Green said: "Although we have not been immune from the effects of the severe de- leveraging of the financial system, we have been able to reinforce and grow some of our most important franchises as other banks have weakened, and this will make us stronger when market stability returns."

Some analysts remained sceptical about the announcement, pointing to gains HSBC made from the decline in value of its own debt.

The big drag on the firm has been its US sub-prime lender HSBC Finance which it acquired five years ago.

Charges for bad debts, primarily from mortgages and credit cards, rose by $700m (£448m) to $4.3bn in its personal financial services division in the US.

The company warned that it might have to cut the value of the division at the end of the year if this continues.

HSBC was also cautious about the prospects for emerging markets, where it has seen booming business, noting that they will see reduced export demand and lower foreign investment as maturer economies are hit by recession.

HSBC has outperformed its peers for much of the year but its relative financial strength has been undermined by the decision of UK rivals such as Royal Bank of Scotland, HBOS and Lloyds TSB, to raise capital underwritten by the government.

Dale Robertson of fund manager Edinburgh Partners, which recently sold its HSBC stake, said: "One of the reasons it has outperformed is that capital strength. When the government money comes onto the balance sheets of HBOS and others, HSBC's competitive advantage disappears a bit."

Abbey owner Santander's rights issue took the market by surprise. Not only has it made UK purchases but it is bidding for the remaining 75% of US bank Sovereign it does not already own.

NAB's move was also un-expected. It initially offered A$2bn in shares at a 10% discount to its closing share price on Friday but after this was oversubscribed increased the size of the issue by 50%.

NAB said the success of the share sale reflected its strong capital base compared to its competitors. It now has the strongest capital base of the Australian banks. It was facing possible downgrades by credit ratings agencies.