There is an idea that makes many investment professionals uncomfortable, yet has been supported by data for decades: most fund managers do not outperform the market. Not systematically, not after adjusting for risk, and especially not after their fees.

This observation gave rise to index funds — one of the most studied, debated, and fastest-growing investment instruments of the past few decades.

The promise of active management

An actively managed fund aims to outperform a reference index — the S&P 500, the MSCI World, the FTSE 100. A team of analysts and portfolio managers studies companies, evaluates trends, makes decisions, and moves capital when they judge it appropriate. A management fee is charged for this work.

The premise is reasonable: if managers are smarter, better informed, or more disciplined than average, they should beat the market. The problem is that the market is not the average — it is the aggregate of all investors. When all active funds buy and sell among themselves, the sum of their results before fees is exactly the market.

What the evidence shows

The SPIVA report, published annually by S&P Global, measures how many active funds outperform their reference index over various time horizons. The results have been consistent for decades:

  • Over one year, between 50% and 60% of active funds fail to beat the index.
  • Over ten years, that figure rises to 80-85%.
  • Over twenty years, it exceeds 90% in most categories.

The pattern is not limited to the United States. Across Europe, emerging markets, and fixed income: the same story repeats. Not all managers perform poorly, but identifying in advance which ones will do well is extraordinarily difficult — even for industry professionals themselves.

Why fees change everything

A management fee of 1.5% per year may seem small. But compound interest works in both directions.

If you invest €10,000 for 30 years at a gross annual return of 7%, the result before fees is approximately €76,000. With a 1.5% fee, the net return falls to 5.5%, and the final result is around €49,000. The difference is more than €27,000 — nearly three times the original investment.

Index funds are designed to replicate an index at the lowest possible cost. Their typical management fees range from 0.05% to 0.25% per year. In a passive vehicle, there is no research team to pay, no frequent portfolio turnover, no discretionary decisions. The fund simply holds the same stocks that make up the index, in the same proportions.

How an index fund works

The mechanics are simple: the fund buys all, or a representative sample, of the stocks that make up a given index, in the exact proportions in which they appear in that index.

If the MSCI World includes 1,500 companies from 23 countries, the fund will hold all of them in the same market-cap weighted proportion. If Apple represents 4% of the index, the fund allocates 4% of its capital to Apple shares.

When the index is reviewed, the fund adjusts. No further decisions are required. The fund’s performance will track the index almost exactly, minus the management fee.

There are two main formats: traditional index mutual funds, which are subscribed and redeemed once a day at net asset value, and ETFs, which trade on an exchange like a stock and can be bought and sold throughout the day. Both can be equally valid — the main differences lie in the investment platform and the applicable tax treatment.

What an index does not solve

Investing in index funds does not eliminate market risk. If the market falls 40%, your fund will fall by roughly the same amount. Indexing does not protect against declines — what it does is ensure you capture the full recovery when the market recovers, without the additional risk of a manager making poor decisions at the worst moment.

It also does not answer questions about how much risk to take, how to allocate across geographies or asset classes, or when to contribute. Those decisions remain yours.

What an index fund does do is remove a layer of complexity and cost that, according to decades of evidence, adds no value in most cases. It is a simple tool with a robust argument behind it.