How can investors know whether a portfolio is active or passive? One metric is called “Active Share.” Active Share measures the degree to which a fund’s portfolio differs from the holdings of its benchmark. The higher the active share number, the more active and independent a portfolio is from its benchmark. An Active Share score of 100, for example, indicates that a fund has perfect independence from its benchmark; an Active Share score of zero indicates that the fund is more like a passive index fund. Active Share is not a predictor of future performance.