The Spectrem Group announced that its Millionaire Investor Index fell to its second-lowest level ever in August, on continued worries about energy costs and the Iraq War.

“The index, which has been in a general downtrend since its near-term peak in February, remained in neutral territory despite the August decline,” the firm noted. At its current level, the millionaire index stands just above its all-time low of zero, which it hit in October 2005.

Similarly, the Spectrem Affluent Investor Index, which measures the investment outlook of households with US$500,000 or more in investable assets, also fell in August to its second-lowest level. It is also at a neutral reading and a single point from its historic low, which also dates to October 2005.

“Millionaires and the broader affluent population appeared unable to look past the continuous flow of bad news in August, pushing the investment optimism of both groups to its second-lowest levels since our tracking began in February 2004,” said George Walper Jr., president of Spectrem Group. ”Millionaires and the affluent have steadily lost optimism since this winter. Concern about oil and gas prices and the Iraq War, as well as housing and real estate, pushed down our millionaire and affluent indexes even further in August. With continued bad news having such a significant impact on their outlooks, one wonders whether we’ll have to wait for some unexpected good news to begin reversing this downtrend.”

In response to an open-ended question about the news event having the greatest impact on their economic outlook, affluent investors cited: oil and gas prices (24%), the Iraq War (16%), housing and real estate (11%), interest rates (5%), the economy (5%) and terrorism (4%). The percentage choosing oil and gas prices rose slightly from 23% in May 2006, the last time this question was asked.

Like the affluent, millionaires also expressed the greatest concern about oil and gas prices at 19%, followed by the Iraq War (14%), housing and real estate (6%) and interest rates (6%).

The Spectrem Affluent Investor Index is based on 250, 10-minute telephone interviews each month, giving the data a margin of error of plus or minus 6.2 percentage points. Interviews are conducted with the financial decision-makers in households with US$500,000 or more in investable assets. The Spectrem Millionaire Investor Index is based on a subset of the overall survey group that can vary each month.