Confidence among millionaire households is still on positive ground, having gained 1 point to end October at +2, representing a six-month high for Spectrem Group's Millionaire Investor Confidence Index.

Meanwhile, despite remaining in negative territory, the Affluent Investor Confidence Index - which measures the investment confidence and outlook of households with $500,000 or more in net worth - climbed up 6 points from -8 to -2 and is now at its highest level since April.

"But while there was an uptick in stock investments among affluent investors, there was no improvement in the number of those who are opting for now to stay on the sidelines," said George Walper, president of Spectrem Group.

Improvement in both indexes can be traced to several factors, the firm said. The Affluent Household Outlook survey, for example, showed "significant increases" across all components including household income, household assets, company health and the economy, which saw the largest increase in over a year. "October was the first time since May when all of the components simultaneously posted positive readings," it said.

Affluent investors cited stock market conditions and - somewhat unsurprisingly given that the US elections are only a week away - the political climate as the factors most affecting their current investment plans.

The Affluent Investor Confidence Index is based on 250 monthly online interviews with the financial decision-makers in households with $500,000 or more in investable assets. The Millionaire Investor Confidence Index is based on a subset of the overall survey group.