New Delhi, July 7 -- Investors in actively managed equity mutual funds pay higher fees on the premise that the fund manager is doing something different than the index-picking stocks, sizing bets, and deviating from the benchmark to generate outperformance. Active share is a simple metric that helps investors check whether their fund manager is taking real active positions or largely sticking to the benchmark index.

Active share measures how different a fund's portfolio is from its benchmark index, expressed as a percentage between 0% and 100%. A score of 0% means the portfolio is an exact replica of the index, while 100% means the fund holds nothing in common with it. Put simply, it tells you what portion of the fund's money is invested...