ETFs and Index Funds in Depth: How They Work and Why They Matter for Long-Term Growth

In the previous post, we explored the transition from building your emergency fund to allocating additional surplus toward an investment portfolio. This allows money you do not need in the near term to grow at a rate far exceeding traditional savings accounts—by accepting calculated risk through assets like stocks, bonds and broad-market funds.

For the majority of individual investors, the cornerstone of this portfolio should be index funds or exchange-traded funds (ETFs) that track established market indices. These vehicles offer an efficient, low-maintenance way to gain exposure to hundreds or thousands of companies simultaneously.

What exactly are index funds and ETFs?

An index fund or ETF is essentially a basket of securities designed to mirror the composition and performance of a specific market index.

Common examples include:

• S&P 500 – the 500 largest publicly traded U.S. companies by market capitalisation
• Euro Stoxx 50 – 50 leading blue-chip companies across the eurozone
• MSCI World – large and mid-cap companies from 23 developed markets globally
• FTSE All-World – broad coverage including emerging markets

A large asset management company (such as Vanguard, BlackRock/iShares, Amundi or State Street) creates the fund by purchasing the underlying stocks (or bonds) in proportions that exactly match the index. The fund provider then issues shares in the fund itself, which investors can buy on the stock exchange.

When you purchase a share of an ETF (e.g., VWCE for Vanguard FTSE All-World or IWDA for iShares Core MSCI World), you own a tiny fractional proportion of every company in that index. If the overall index rises by 8 % in a year, your ETF share value should rise by approximately the same amount (minus small fees).

Key structural differences

• Traditional index mutual funds are priced and traded once per day at the net asset value (NAV).
• ETFs trade throughout the day on stock exchanges like individual stocks, offering greater liquidity and flexibility. Most retail investors today prefer ETFs due to lower minimum investments and real-time pricing.

In practice, the terms are often used interchangeably for passively managed, broad-market products.

Costs:

The fund provider handles:

• Buying and rebalancing the underlying securities to match the index
• Administrative and regulatory compliance
• Dividend collection and reinvestment (in accumulating ETFs) or distribution (in distributing ETFs)

For this service, they charge an annual expense ratio or total expense ratio (TER), typically ranging from 0.03 % to 0.40 % depending on the fund’s complexity and provider. Popular global equity ETFs often fall in the 0.07–0.25 % range.

Example current TERs (as of late 2025):

• Vanguard FTSE All-World UCITS ETF (VWCE): ~0.22 %
• iShares Core MSCI World UCITS ETF (IWDA): ~0.20 %
• Amundi MSCI World UCITS ETF: ~0.12 %

These fees are deducted automatically from the fund’s assets, so you see only the net return. Over decades, the difference between a 0.20 % fee and a 1.0 % active fund fee can amount to tens or hundreds of thousands of euros due to compounding.

Advantages in more detail

1. Instant diversification – exposure to thousands of companies reduces the impact of any single company’s poor performance.
2. Passive management – no expensive stock-picking team; the fund simply follows the index, which historically outperforms most active managers after fees (as shown in regular S&P SPIVA reports).
3. Transparency – holdings are published daily.
4. Tax efficiency – especially accumulating ETFs in many European jurisdictions (dividends are reinvested before tax events).
   Accessibility – available through almost every broker with no or minimal transaction costs.

Risks to understand

While far less risky than individual stocks, broad-market ETFs are not risk-free:

• Market risk: if global equities decline (as in 2008–2009 or 2022), the ETF value falls accordingly.
• Currency risk: for euro-based investors holding USD-denominated assets.
• Tracking error: tiny deviations from the index performance (usually negligible in established funds).

These products are designed for long-term horizons (10+ years), where historical data shows positive real returns in the vast majority of rolling periods.

In the context of the allocation example from recent posts (€200 monthly once the emergency fund is progressing), directing this into a single global equity ETF provides a straightforward, evidence-based path to participating in worldwide economic growth—while you continue focusing time and energy on personal development and career. Try out our investment calculator to play around with past market performance by changing the investment amount and timing.

If you already hold ETFs or index funds, which specific ones form the core of your portfolio and what led you to choose them? Or if you are researching options now, what criteria matter most to you (cost, geographic coverage, accumulating vs distributing, etc.)?