Finding a mutual-fund manager who can beat the market is tough. Winners flame out. Losers revive. The resurgent losers flame out again.
No wonder low-cost index-based exchange-traded funds and mutual funds—which seek only to mimic the return of a designated slice of the market—have eclipsed actively managed funds as the investment of choice for many people.
... One problem: Over long periods, few fund managers continue to outperform, says Laurent Barras, a finance professor at McGill University in Montreal.