Despite February's climb into bullish territory for the first time since October 2007, the Spectrem Millionaire Investor Confidence Index (SMICI) fell back into neutral territory for March.

The monthly index saw an impressive 15 point jump to 17 in February, but fell 9 points to 8 for March. Despite the decline, the index is at its highest level since December 2007, when the index stood at 8.

Confidence amongst affluent investors also fell in March. The Spectrem Investor Confidence Index (SAICI) fell 3 points this month to a neutral level of 1, according to Spectrem Group. The SAICI is based on 250 monthly interviews with the financial decision makers of households with $500,000 or more in investable assets. The SMICI is based on a subset of overall group.

"Millionaires' investment confidence fell in March, erasing more than half the prior month's gains and returning it to a neutral stance from mildly bullish. Confidence also slipped among the broader affluent population. With the economy and political environment ranking as their top sources of concern, it appears America's wealthiest investors have added a solid dose of caution to their investment outlook," said George H. Walper Jr., president Spectrem Group.

When affluent investors were asked what are the most serious threats to achieving their household financial goals, 22% said the economy, 22% said the political climate, and 10% cited unemployment. Millionaire investors also ranked the economy (25%) and the political climate (19%) as their top concerns.

The SAICI also showed the number of investors who chose not to invest in March rose to 22.8 points, a two point bump from February. Investment in cash was down slightly more than than a point, dropping to 49.6 points from 50.8 points last month.