Asset Allocation — What It Means and Why It Explains 90% of Your Returns

The energy most investors spend: which fund, which stock, which platform. The decision that actually determines their outcome: what percentage of the portfolio sits in equities versus bonds and cash. Decades of research attribute the vast majority of a diversified portfolio's return variability to this split — the allocation — with security selection and timing fighting over scraps.

That's uncomfortable, because the allocation is the least glamorous decision available. It's also liberating: the decision that matters most is one you can make deliberately, once, in an afternoon.

What the split actually controls

Equities are ownership: the engine of long-run returns and the source of the drawdowns — periodic falls of 30–50% are a feature of the asset class, not a malfunction. Bonds and cash are the shock absorber: lower expected returns, radically smaller falls, and the dry powder that lets you rebalance into a crash rather than sell into one.

So the equity percentage is really answering one question: how much interim loss can this money's purpose and this household's nerves sustain, in exchange for higher expected long-run growth? An 80/20 portfolio should expect roughly double-digit-times-something falls on the way to its returns; a 40/60 gives up growth to halve the turbulence. Neither is "better" — they're priced for different jobs.

Allocation follows the goal, not the person

The practical unit is the pot, not the person. Retirement money with a 25-year horizon can carry high equity weight — it has time to outlive several drawdowns. A property deposit needed in four years carries almost none, whatever your risk appetite. A Swiss household often holds three or four allocations simultaneously (3a, taxable portfolio, deposit fund) — and that's correct, not inconsistent.

Two Swiss-specific notes: your Pillar 2 is already a large, conservative allocation — counting it as part of household wealth argues for the free portfolio carrying more equity than a standalone questionnaire would suggest. And home bias — overweighting Swiss stocks because they're familiar — concentrates risk in one small economy your salary already depends on; global diversification is the cheap fix.

Set it, write it, rebalance it

An allocation only works if it's maintained: markets drift it (a 60/40 becomes 75/25 after a good equity run — more risk than you chose, precisely when prices are highest). Rebalancing — once a year, or at a drift threshold — mechanically sells high and buys low, without requiring a view.

Write the target down (see the Investment Policy Statement article). An unwritten allocation renegotiates itself every time markets make headlines.

What are you optimising for?

Growth, stability or a date — each pot has one primary answer, and the split should say it out loud.

Control questions: Can you state your current overall equity percentage — calculated across accounts, not guessed? Was it chosen for the goal, or inherited from whatever you happened to buy? And when did you last rebalance back to it?