Active Index Fund

A type of index fund where a fund manager bases the fund's initial investment proportions according to the benchmark index in which the manager is attempting to track, and then proceeds to add what he/she believes to be higher performing stocks that are unrelated to underlying index. The fund manager will then actively manage the composition of these non-benchmark stocks in order to earn yields that exceed the benchmark index.

Taobiz explains Active Index Fund

A fund manager that attempts to make an active index fund version of the Standard & Poor's 500 Index (S&P 500) would buy and periodically rebalance all the stocks to match the proportions found in the actual S&P 500. In addition, the manager will add stocks they believe will have a strong performance. For example, if the manager believes that the semiconductors will be hot during the subsequent quarter; more semiconductor stocks would be added to the portfolio.

While it is possible that some fund managers may be able to significantly beat the underlying benchmark index by using strategies, such as market timing, this is far from guaranteed. Furthermore, the active management aspect of the fund will likely incur higher expenses, which could eat away at some and perhaps all of the extra returns earned by active management.