You can probably say what your rent or mortgage costs, roughly what the energy bill runs to, and within twenty pounds what a weekly shop comes to. Now try this one: what percentage does your pension charge you each year?
Most people cannot answer. Not because it is hidden — it is disclosed, in a document that arrives annually and goes straight in a drawer — but because it is written as a decimal that looks like nothing. Nought point seven five. One point two. Numbers that size do not feel like money.
John Bogle built a career on the observation that they are the largest financial decision most people never consciously make.
The arithmetic nobody runs
The reason a small percentage matters is that it does exactly what you are hoping your savings will do. It compounds.
Everyone understands compounding when it is working for them: money left alone grows on its own growth, and forty years turns a modest amount into a large one. The fee runs on the same engine in the opposite direction. It is not taken once. It is taken every year, on the whole balance, including on all the growth that the previous years' fees already prevented.
Run it and the result is genuinely hard to believe the first time. Over a working lifetime, a difference of one percentage point a year does not cost you one percent. It compounds into a fifth or more of the final pot — the exact figure depending on the horizon and the return, neither of which anybody can promise you. That is not a fee. That is a share of the outcome, taken by someone whose contribution you never see and cannot easily assess.
Bogle's point was about which numbers you actually control. You cannot set your returns. You cannot know what markets will do, and he distrusted anybody who claimed otherwise. But the cost of the arrangement is knowable in advance, fixed in a document, and the only variable in the whole exercise you can establish with certainty before committing to anything.
Which is why the first question is what the arrangement costs you, not what to put inside it — and why almost everybody asks it the other way round.
Watch out for
The failure of this idea is the version of it that goes one step too far, and it is a real risk once the arithmetic lands.
Cost is the variable you can be certain about, which makes it seductive as the only variable. Someone who has just discovered the compounding-fee problem can talk themselves into whatever is cheapest without asking whether it suits their situation at all — their age, how long the money has to last, how much of a fall they could actually live through without selling at the bottom. The cheapest arrangement that you abandon in a bad year costs more than a slightly dearer one you can hold. Bogle's own method depended entirely on holding, and the fee was never the point on its own.
Two other things this reasoning will not do for you. It will not tell you what to buy — that needs your figures, your horizon, and someone licensed who knows your circumstances, and anyone offering it from a blog post does not have any of those. And it is not a forecast: none of this says what markets will do, because the whole approach was built to avoid ever needing to know.
Answer this next
Find the annual charge on the largest pot of money you own — the pension, the ISA, whichever is bigger. It is in the annual statement. What is the number?
