Despite an increase in affluent investor confidence, millionaires are “uneasy” about the economy.

Spectrem Group’s Affluent Investor Confidence Index rose three points to negative-10 in February, returning to neutral territory for the first time since November. The index, which measures the investment outlook of households with $500,000 or more in investable assets, increase follows a two-point advance in January and brings the index to neutral from mildly bearish for only the second time since February 2008.

The Spectrem Millionaire Investor Confidence Index fell one point in February to negative–10 to record its seventh consecutive neutral reading.

“Affluent Americans became slightly more confident about investing in February as millionaires saw their confidence slip,” George H. Walper, Spectrem’s president, said in an interview Wednesday. “This left both groups with identical confidence readings, an unusual situation since millionaires have historically been more optimistic than the affluent, suggesting deep-seated unease among millionaires about both the economy and issues surrounding it.”

In response to an open-ended question about the issue most affecting their economic outlook, affluent investors in February cited: the political environment (26%); unemployment (14%); health care reform (12%); the economy (10%); stock market conditions (4%); and housing and real estate (2%). Those choosing the political environment rose from 7% in November, the last time this question was asked, and those choosing unemployment rose from 11%.

Millionaires expressed slightly less concern than the affluent about both the political environment (25%) and unemployment (13%).

The affluent index is based on 250 monthly interviews conducted by Chicago-based Spectrem. The millionaire index is based on a subset of that survey.