We construct new measures of fund style, performance and activity from linear combinations of off-the-shelf stock-market indices. A fund's benchmark portfolio is a linear combination of two or more reference portfolios that in a least-squares sense most closely approximates the fund's portfolio. The resulting linear combination scalar is itself a measure of fund style and the distance between a fund and its benchmark is a measure of fund activity. Our approach has a number of advantages over existing characteristic-matching methods. We illustrate our approach using a data set of US institutional funds.