Lump Sum or Savings Plan? The Honest Answer

"Should I invest it all at once or spread it over twelve months?" The question appears whenever a larger amount becomes available: an inheritance, a bonus, the sale of a property, a pension payout. And it usually gets answered with a gut feeling rather than with numbers. Let us look at both.

01What the data says

Research on this question has reached the same conclusion for decades. Investing an available amount immediately produces a better final result than staggering it over six or twelve months in roughly two cases out of three, across different markets and periods.

The explanation is unspectacular. Staggering means holding part of your money in cash for longer on average. Cash earns less than the equity market. Across the majority of periods, that waiting costs more than the smoothed entry prices deliver.

An example: CHF 60,000 invested over 20 years at a 7% annual return. Invested immediately, that becomes roughly CHF 232,000. Spread across twelve monthly tranches of CHF 5,000 and then left to run for 19 years: roughly CHF 224,000. A difference of about CHF 8,000, just over three percent — in an average outcome.

02Why the question is usually framed wrong

The entire debate assumes a larger amount is sitting ready. For most people it is not. They do not have wealth waiting to be invested — they have an income with something left over each month.

For that money the alternative does not exist. You cannot invest CHF 500 a month "all at once", because it only comes into being month by month. In that situation a savings plan is not the second-best choice; it is the only sensible way to move ongoing income into the market.

So the honest version of the question is not either-or, but: what do I do with my monthly surplus — and what do I additionally do with amounts that arrive outside that rhythm?

03The argument no study contains

Suppose you invest CHF 200,000 in one go, and three months later a 30% correction begins. On paper you have lost CHF 60,000. Statistically your decision was still correct. Emotionally you will see it differently — and the decisive question is not who is right, but what you do in that moment.

Selling at that point converts a temporary paper loss into a permanent one. The statistically superior strategy has then become the worse one in practice — not because of the mathematics, but because of its survivability.

04When staggering genuinely makes sense

There are situations where staggering is defensible on the merits, not just psychologically.

When the amount is very large relative to your total wealth. Someone who has invested CHF 20,000 so far and suddenly inherits CHF 400,000 changes their risk profile overnight. Here a transition over a few months is less a question of return than of adjustment.

When your horizon is short. With five years until the money is needed, the market has less time to make up for an unlucky entry. At that point the equity allocation matters more than the entry method anyway.

When otherwise you would not dare at all. A staggered entry that happens beats a lump sum that never happens out of fear. Not an elegant reason, but a real one.

What makes sense in none of these cases: staggering across several years. Spreading CHF 100,000 over five years is no longer risk management — it is simply holding too much cash permanently. Six to twelve months is the usual range.

05The combination that actually works

In practice the two approaches need not exclude each other. A three-layer structure works well.

The third layer is the real difference between a standing order and an investment strategy. It requires neither a forecast nor market timing in the narrow sense. It only requires the willingness to buy more at minus 20% rather than less — and ideally to keep some liquidity set aside for exactly that.

What such a moment looks like in practice, and what tends to go wrong, is covered in Markets Down 20%: What to Do Now.

06Frequently asked questions

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