Lump sum investing: should you put 500.000€ to work now?

This summer, Marc, 65, saw 500.000€ land in his account in one go when his group insurance, his occupational pension plan, paid out.

He would like to invest the money in the stock market, but is this really the right time? Markets have just hit a record high. Should he invest now, at top prices, or wait for a dip that may never come?

We went back over 27 years of stock market data to answer Marc's question, and that of everyone wondering when to get started.

When to invest?

More often than not, the best time to invest is now!

Since 1999, waiting for a 10% fall after a record high has cut the final result by 20% on average. Investing a lump sum in one go also beat spreading it over twelve months in 68% of cases. On the statistics alone, waiting does not pay.

Waiting for a dip is costly on average

When markets hit a record, the temptation is to hold off until a correction, a fall of at least 10%. That approach assumes the fall actually comes, and soon enough to make the wait worthwhile.

We calculated what this strategy would have delivered since 1999. Whenever the market stood close to a record high, our investor kept the money in a savings account and waited for prices to drop 10% below their starting level before investing. We then compared the outcome with that of an investor who put everything in straight away.

• In 46% of cases, the 10% fall never came, so the money was never invested at all. On average, the patient saver ended up with 63% less than the investor who went in immediately.
• In the other cases, the fall did come and the wait paid off. The patient saver finished with 16% more on average.

The bet is therefore lopsided: a small gain against a heavy shortfall, roughly one time in two. Across all cases, waiting for a 10% fall cut the final result by 20% on average, which makes it a losing bet statistically.

Phased investing proves less attractive

Investing a lump sum and waiting for a dip are not the only options. You can also invest in instalments, for instance a twelfth of the sum each month for a year. This is known as phased investing, or dollar-cost averaging (DCA).

Is it better to invest gradually or in one go?

For every month between 1999 and 2025, we compared the capital obtained after one year by investing in one go with the capital obtained by spreading the investment over twelve months.

The verdict is clear: investing in one go did better in 68% of cases.

The explanation is simple: over the period studied, shares rose in three twelve-month periods out of four. Every month spent out of the market therefore deprives your money of a likely gain.

So why might spreading still make sense?

Spreading does have one advantage: it limits the damage in a worst-case scenario where the market drops sharply during the year. It cannot shield the portfolio from the fall, but it can soften the blow.

1. The worst case was a start in March 2002, in the middle of the crash that followed the dotcom bubble. A year later, 500.000€ invested at once was worth just 302.000€, against 412.000€ when the investment was spread.
2. Conversely, at the end of March 2020, as stock markets rebounded after the Covid crash, 500.000€ invested immediately was worth 716.000€ a year later, while a phased investment reached only 599.000€.

In short, spreading the investment makes a nasty surprise easier to live with. It does not avoid the fall altogether, however. If markets rise sharply, it can also carry a significant opportunity cost, meaning the gains you miss out on.

A defensive profile favours investing immediately

Before choosing between investing in one go or gradually, you need to determine the risk profile that suits your situation. A defensive profile, made up mostly of bonds with a limited share of equities, is far less exposed to market swings. With 30% in equities, for example, a 20% stock market fall would cost only about 30.000€ on 500.000€, assuming bonds hold steady. The risk of bad timing is then limited, and spreading loses most of its appeal: with a defensive profile, or a neutral one split roughly evenly between equities and bonds, investing immediately is the natural choice. You also keep some room for manoeuvre: after a fall, you could switch to a more dynamic profile and buy at lower prices.

Investing immediately remains the best option statistically

All in all, investing immediately is the best option in most cases, whether markets have just fallen or are at a record high: over 27 years, it came out ahead slightly more than two times in three. When spreading did better, it mainly limited a loss.

These results assume a discipline that can be hard to stick to, however. At Easyvest, we see many people who spread their investment suspend their payments when the market falls, just when they should carry on or even speed up. Those waiting for a dip often lose patience and end up investing at the top, sometimes just before the correction.

Spreading is therefore only justified in specific cases: a large sum (over 100.000€) currently held in cash rather than in a portfolio that is already invested, spread over a short period of three to six months, either for a risk profile heavily exposed to equities or for an investor who finds the prospect of a fall stressful. In that case, spreading works like insurance against a sharp fall just after you start. Like any insurance, it has a cost, namely the return you miss when the market rises. It only pays out if the fall is sharp and rapid, and provided you keep investing during it.

Whatever you decide, the most important choice is a risk profile you can stick with over time. The Easyvest simulator helps you find it based on your amount, your time horizon and your goal, whether a monthly income or growing your capital, and shows how your capital could develop in good and bad scenarios alike.

Investing in one go, with a risk profile you can hold on to through the bad days, remains the surest way to grow a large sum, and spreading only makes sense if it helps you stay invested.

Past performance is no guide to future performance. The figures in this article are historical simulations and do not constitute personalised advice.

Sources: MSCI, World Index in euros, net dividends reinvested, historical levels · ECB/NBB, interest rates on Belgian households' regulated deposits (MIR series) · Vanguard Research, B. Wimmer, A. Shtekhman and C. Tasopoulos, "Dollar-cost averaging just means taking risk later" (2012) · Easyvest, "When is the right time to invest?" (2025) · Easyvest calculations, January 1999 to September 2026