Fund managers do have a better understanding of businesses than retail investors. But picking the same stocks that they have may not work for the latter for several reasons. The data that mutual funds release comes with a lag. By the time you get to know of a pick by the fund manager, the latter may have already exited it. An investor cannot get to know the price the fund manager paid, or his objective behind the stock pick. Also, fund managers sometimes buy index stocks to ensure returns at par with the benchmark.