Strategy & FAQ
How to Rebalance Your Portfolio
A portfolio built five years ago with a 60% stock and 40% bond split can drift to roughly 72% stock after a strong run in equities. That quiet shift...
Why Asset Allocation Matters More Than Fund Picking
A surprising amount of investing energy goes into choosing between two funds that own almost exactly the same companies. Their expense ratios differ by a few hundredths of a percent, their top holdings overlap heavily, and their ten-year charts sit on top of each other. Meanwhile the decision that will dominate the outcome, how much of the portfolio sits in equities versus bonds and cash, often gets made once by default and never revisited.
This is not a claim that costs are irrelevant. It is a claim about scale. A difference of a few basis points in fees is a small, steady drag. A difference of twenty percentage points in equity exposure changes the size of every drawdown you will ever sit through, and therefore changes how likely you are to keep the plan at all.
Where the variation actually comes from
Academic work on portfolio returns has long made an uncomfortable point for stock pickers: the broad mix of asset classes explains most of the variation in results over time, while security selection and market timing explain comparatively little, and often explain negative amounts after costs. You do not have to accept every detail of that literature to take the practical lesson. The big lever is the mix.
Consider two portfolios built from the same broad equity fund. One holds 90 percent of it and 10 percent in bonds. The other holds 60 percent and 40 percent. Over any stretch containing a serious decline, their experiences are completely different: the first falls much further, recovers faster if you stay invested, and demands far more nerve. Choosing a marginally cheaper share class of the equity fund barely registers next to that.
The behavioural version of the argument
Even if you had the stomach for a very aggressive mix, the relevant question is whether your actual household does. A portfolio that is theoretically optimal but causes someone to sell in the third month of a decline is worse than a slightly more conservative one that gets held for fifteen years. The best allocation is not the one with the highest expected return on a spreadsheet. It is the one you can keep funding through a bad year.
That is why the honest exercise involves imagining a specific bad month: prices down a quarter, a grim headline every morning, a colleague asking whether you have moved to cash. If the honest answer is that you would sell, the mix is too aggressive regardless of your age or your horizon.
What to do with that insight
- Write the target mix down as a range, with a reason tied to the date you will need the money.
- Choose cheap, broad funds to fill each side of it, then stop comparing near-identical products.
- Rebalance on a fixed schedule, preferably by directing new contributions to whichever side is underweight.
- Change the mix only when the goal or your genuine tolerance changes, not when a forecast does.
- Spend the time you saved on the contribution rate, which for most people moves the final number more than any fund choice.
The contribution rate is the other big lever
For someone in the first decade of building a portfolio, the balance is dominated by money they have not yet contributed. Raising a monthly contribution by a modest amount has a larger effect on the balance ten years out than shaving a few basis points off a fee. Yet the fee comparison feels like diligence and the contribution rate feels like budgeting, so the former gets the attention and the latter gets ignored.
This is a pattern worth noticing: the decisions that feel most like investing are often the ones with the smallest effect. The decisions that look like ordinary household administration are the ones that compound.
What about the funds, then
Pick broad, low-cost, transparent holdings and then largely forget about them. That is not laziness; it is an acknowledgement that once a fund is cheap and genuinely diversified, further optimisation has very little left to extract. A handful of sensible holdings, a written target mix, and an automatic contribution will beat an elaborate portfolio that requires constant attention.
There is a useful test before you spend an evening comparing two nearly identical products: write down how much the decision could plausibly change your result over ten years. If the answer is a fraction of a percent, close the tabs. Then look at your allocation range and your monthly contribution, where the answer is not a fraction of a percent at all.
The boring conclusion is also the liberating one. You do not need to find the best fund. You need a reasonable mix, a low bill, and the patience to keep paying into it.
