New York consultants Spectrem Group say their Millionaire Investor Index, which measures the investment outlook of households with at least $1 million in investable assets, fell 13 points last week to minus 34, reflecting growing economic concerns.

The figure is the second lowest level since the survey was started in February 2004. Any reading below minus 31 represents bearish territory, says Spectrem. The group's Affluent Investor Index, a companion survey, also fell in February, sliding 10 points to minus 38.

"With both groups' concerns over the economy skyrocketing despite government stimulus plans, it is clear that the wealthiest Americans feel the crisis remains far from a turning point," said George Walper, president of Spectrem, in a statement.

The record low for both indexes is minus 39, a level that was reached in November when stocks fell to 11 year lows. Both the millionaire and affluent indices were out of bearish territory in January, with readings of minus 28 and minus 21, respectively.

The markets have been plagued with dire news since then. AIG reported the largest quarterly loss in US corporate history and the US government said it could boost its stake in Citigroup to as much as 36 per cent.

In response to an open ended question about the news story most affecting their economic outlook, 60 per cent of affluent investors in February cited the economy while 10 per cent said stock market conditions, 5 per cent said housing and real estate conditions and 4 per cent said the political climate.

In November, the last time the question was asked, 42 per cent said the economy and 17 per cent said stock market conditions. Spectrem's Affluent Investor Index is based on monthly interviews with 250 financial decision makers in households with at least $500,000 in investable assets.