Fears for the sustainability of a global economic recovery have led the world's wealthiest families to increase holdings of cash, gold and bonds, a survey published has shown. The super rich, with more than $200 million in investable assets, have high cash holdings despite low returns, according to research by the newly formed Family Office Channel.

"Many of the world's richest families have had their confidence in their tax status, their advisers and their investments shaken by key events over the last year," the report said.

Of the 100 global respondents, many said they were dividing up cash holdings among insured accounts and funds to take advantage of state guarantees on deposits.

About two-thirds said they were more likely since the financial crisis to invest in commodities, including gold, while the preference for bonds was 59 per cent.

Commercial property, equities, hedge funds, private equity and structured products all remain out of favour with the super rich, the survey said.

The tax row between the US government and UBS, the world's largest wealth manager, plus tax amnesties on offshore investments from the US, UK and Italy have also shaken confidence. More than half of the families surveyed have reviewed their tax position as a result of the amnesties but some are fearful of criminal sanctions and fines and others were confused about how far back historic assessments would go.

John Riches, a partner at law firm Withers Worldwide, said families were primarily worried about the resources needed to comply with the amnesties if old records prove inadequate to the demands for disclosure.

"The process might be disproportionately expensive to the tax you are after," he said.