Macquarie, Australia's top listed investment bank and owner of M6 Toll operator Midland Expressway, beat forecasts with a 45 per cent jump in first-half profits thanks to higher fees from Asian equities trading.

However, it was not all good news for the bank as investors reacted badly to its prediction that the continuing volatility in equity markets was likely to mean its second-half result would only match that of last year.

Investors had been looking for an upgrade to earnings forecasts.

Chief executive Allan Moss said: "Market conditions are generally very volatile and frankly somewhat nervous."

Despite its gloomy forecast, Macquarie has faired better than the troubled Wall Street investment banks, many of which have writ-ten off billions of dollars due to their exposure to distressed sub-prime mortgage loans. Macquarie has been insulated from the problems due to its lack of involvement in that area, a position it reiterated yesterday.

"We are not involved in subprime in the US at all," said Mr Moss.

He added that despite the situation, the bank was not unduly pessimistic about the US economy at this stage.

Macquarie, which completed a restructure earlier this month to accelerate global expansion, said net profit in the six months to September rose to £455 million. There were no unusual provisions or writedowns in the results, it said.

Analysts on average had projected Macquarie's profit to rise 40 per cent to £438 million.

The bank did not release quarterly figures, but said its second-quarter profit was down 17 per cent on the first quarter, as global investment banks suffered due to credit turmoil.

A pull-back in global equity markets could potentially impact demand for assets Macquarie sells from its balance sheet and other managed funds. Macquarie had £515 million worth of unrealised gains at the end of September, including assets such as European Directories and Thames Water. The bank sold its stake in Birmingham International Airport earlier this year.

Paul Biddle, a fund manager with Souls Funds Management, said: "It just seems that Macquarie is not immune to what is happening in the credit market."

He said Macquarie's comments suggested its full-year profit could land at the lower end of market expectations, which range from £730 million to £841 million.

Macquarie, which advised on 145 deals worth £39 billion in the first half, said investment banking was quieter in US and Europe.

Strong conditions in Asia boosted Macquarie's regional broking business and lifted international income by 70 per cent.

Mr Moss said the first-half result had benefited from a high number of asset sales that were unlikely to be repeated in the second half.

Prominent asset sales in the first-half included stock market float of mining services company Boart Longyear and Taiwan Broadbank Communications.

Apart from its traditional investment bank operations, Macquarie also manages about £96 billion worth of infrastructure assets, such as toll roads like the M6 Toll and airports, which it bundles into listed and unlisted funds.

It earns fees in return for managing these assets, which jumped about 50 per cent in the second half to £205 million.

Macquarie raised almost £6 billion from global investors in the first half, reflecting the continued appetite for infrastructure investments from global pension fund managers.