costs
Costs are the line you can control
The rule
Returns are uncertain and cannot be commanded; costs are certain and can be. So control the one part of the result you actually get to choose.
Where it flips
Cutting cost cannot rescue a plan that owns the wrong thing or tracks its index poorly. A cheap fund pointed at the wrong market is still wrong. Cost is the line you can control, not the only line that decides the outcome.
Malkiel's practical lesson: an investor spends most energy trying to guess returns, which stay stubbornly unpredictable, while ignoring the one input that is fully known in advance: cost. You cannot make the market rise. But you can choose a 0.2% fund over a 1.2% one, and that choice is locked in before any result arrives. Because guessing is so uncertain, the part you can control deserves far more attention than it usually gets. On a fund factsheet, the expense ratio, exit load, and tracking difference are not side details. They are the part of the future you can decide today. Stop trying to control what you cannot, and be strict about the one number you can.
A worked example
Two investors buy the same market exposure; neither can know next year's return. But one deliberately picks the 0.20% fund and the other shrugs at a 1.20% one. The only difference either of them truly chose was the cost. [illustrative]
How to spot it
- ·you spend attention on the known cost, not just the guessed return
- ·you read the expense ratio before the past performance
- ·you do not treat a forecast as if it were as certain as the fee
Burton Malkiel · A Random Walk Down Wall Street