Typically, fund managers pick stocks by looking at companies' balance sheets, sales and profitability growth, and future prospects. But momentum mutual fund schemes bet on the past performance. The strategy entails buying shares when they do well on markets and selling them when their prices start to decline. Back-tested data shows that momentum strategy outpaces broader markets during rising markets, but underperforms in falling markets. At the moment, there are nine index funds and exchange traded funds tracking the two momentum-based Nifty indices. Momentum strategy is best followed through a passive fund route, and not by directly buying stocks.