Commodities are back in investors' good books for the first time in eight months amid a marked improvement in hope about for the global economy, Merrill Lynch has said.

Fund managers are placing - marginally - larger bets than they have historically on commodities, the investment bank said after a survey of more than 200 investors managing $561bn between them.  

Investors have not been "overweight" commodities since August last year, shortly before the collapse of Lehman .

The shift reflected a marked rise in confidence about global economic growth, and particularly about prospects for China, with optimism for the emerging market giant at its highest level since 2003.

"Investors looking to play the global recovery are using China and emerging markets, rather than Europe or Japan, to do so," said Michael Hartnett, co-head of international investment strategy at Banc of America Securities-Merrill Lynch Research.

The report added: "Commodities, integral to emerging market growth, are increasing in popularity."

'Apocalyptic to reluctant'

The improvement was also reflected in equity investment decisions, with fund managers raising positions in basic materials companies at the expense of sectors such as pharmaceuticals, which are typically a refuge in difficult times.

However, ML said that the survey showed fund managers were still treading cautiously.

"The consensus has shifted from apocalyptically bearish to reluctantly bullish," Mr Harnett said.

"But it's important to note that asset allocators are still underweight equities, indicating they have yet to fully embrace the idea of a new bull market."