Investors collectively spend around $100 billion a year trying to beat the stock market. That’s the finding of a rigorous effort to measure the total costs of Americans’ efforts to surpass the returns they would have received by simply holding a stock index fund. The huge price tag helps explain why beating a buy-and-hold strategy is so difficult.

Here is much more, and from Felix Salmon. You can think of this sum as the amount it costs to keep markets relatively efficient, a source of societal fraud and rent-seeking, a Nash equilibrium mixed strategy (no one tries to beat the market on every margin), a donation to the broader social good, or most properly all of the above. Interfluidity adds comment.