OBSR: Our top US funds

US market indices are notoriously difficult to outperform. We think there are few reasons for this: the market is well analysed and relatively efficient making it more difficult to achieve an information edge; the S&P 500 index is an actively managed index which can change at any time (the S&P 500 committee not only considers corporate actions but also makes subjective judgments on company and sector weightings in the index – the majority of changes in other indices are rules-based); an increase in the volume of trades from hedge funds and other high frequency trading vehicles which can dis...