By Gabriele Denaro · Published 20 September 2026 · Updated 6 October 2026
If you have a lump sum to invest, you can put it in all at once or spread it over several months in equal parts, which is called dollar-cost averaging (DCA). Spreading is also what happens naturally when money arrives monthly from your salary. Here the question is only about a sum you already have.
Vanguard studied this with historical data from several markets, including the United States, Europe and Australia. In its February 2023 paper, investing the whole sum immediately did better than spreading it out in roughly two thirds of the historical periods. The reason is simple: stocks and bonds have beaten cash more often than not, so money waiting in cash goes without that edge for a while.
Spreading the purchases means you never put the whole amount in just before a fall. If the market drops early, DCA comes out ahead. If it keeps rising, the lump sum does. You cannot know which in advance, which is why this is a decision about how you will feel as much as about expected returns. With €12,000 you can invest everything today or €1,000 a month for twelve months. The second will usually trail a little in a rising market and will protect you in a falling one.
Money waiting to be invested earns little and loses ground to inflation. That is the price of the comfort. If you choose to spread the purchases, a short window, say three to twelve months, keeps that cost small. Stretching it over years is a different decision with a larger cost.
Neither approach is wrong. One favors the expected outcome and the other the emotional experience of getting there, and the second matters more than a spreadsheet suggests: a plan you stick with beats a theoretically optimal one you abandon halfway. This is general information, not a recommendation for your situation.
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