Most long-term investors in Europe, including those in Romania, have heard the terms passive and active investing. Yet the difference between them is often explained in jargon rather than first principles. This article starts from the basics: what it means to invest passively, how index funds and ETFs do it, why fees matter so much, and why the evidence suggests that a mostly passive approach tends to win over decades.
If you are new to the topic, you may want to read What are ETFs? and Investing in ETFs — a beginner's guide for a broader introduction to exchange-traded funds.
What passive investing means
Passive investing means constructing a portfolio to match the performance of a chosen benchmark, rather than trying to outguess the market. The most famous benchmark is the S&P 500, a market capitalisation-weighted index of the 500 leading publicly traded companies in the United States, overseen by S&P Dow Jones Indices. Since 1957, the S&P 500 has delivered an average annual return of 10.51% (6.64% adjusted for inflation). A $100 investment in 1957 would have grown to over $98,000 by May 2026.
Investors cannot directly buy the S&P 500. Instead, they use index funds or ETFs such as the SPDR S&P 500 ETF Trust (SPY) that closely track the index. The goal is not to beat the benchmark, but to own it cheaply and reliably.
How index funds and ETFs work
An index is simply a rules-based list of securities. When an index adds or removes a company, the fund that tracks it buys or sells the same stock in the same proportion. This process is called replication. Because the fund follows a formula rather than a manager's judgement, it achieves broad diversification in a single instrument: one trade gives you exposure to hundreds or thousands of companies.
No stock-picking or star fund manager is required. The fund's job is to hold the same weights as the index, minus the cost of doing so. This simplicity is a key reason why passive products have grown so fast. Between 2014 and June 2024, EU-domiciled ETFs grew at a compound annual growth rate (CAGR) of 20.7%, more than three times the growth rate of non-ETF funds.
The fee advantage
Every fund charges an expense ratio, the annual fee expressed as a percentage of assets. It is calculated as Total Fund Operating Expenses / Average Net Assets and covers portfolio management, overhead, administration, and marketing. Because passive funds follow a rules-based process with minimal trading, their costs are low. Actively managed funds employ research teams, pay star managers, and trade more often, all of which push costs higher.
Passively managed index funds/ETFs typically have expense ratios of 0.02%–0.25% (e.g., Vanguard S&P 500 ETF at 0.03%), versus 0.50%–1.50%+ for actively managed funds. At the end of 2025, passive equity ETFs had an average expense ratio of 0.14% and bond index funds 0.09%, versus 0.44% for active equity ETFs and 0.33% for active bond ETFs. The asset-weighted average expense ratio for active US equity funds was 0.60% in 2024, versus 0.11% for all passive funds.
Small fee differences compound dramatically over decades. The table below illustrates the impact on a $10,000 investment earning 10% gross annually over 20 years.
Over 20 years on a $10,000 investment earning 10% gross annually, a 0.05% expense ratio leaves about $66,666 (≈$285 in fees), while a 2.5% expense ratio leaves only about $42,479 (≈$10,826 in fees). That is a difference of roughly €24,000 from fees alone.
The evidence on active management
The SPIVA scorecard provides one of the most comprehensive views of active management performance. Per SPIVA data (as of Dec 31, 2024), 65.24% of U.S. large-cap active funds underperformed the S&P 500 over 1 year, 84.96% over 3 years, 84.34% over 10 years, and 89.50% over 15 years. After 15 years, the odds are about 1 in 10 of having picked an active large-cap fund that outperformed the S&P 500; over 20+ years, practically nobody has beaten the benchmark net of fees.
SPIVA reports similar underperformance data for active managers in Europe, Japan, Canada, Mexico, Brazil, Chile, the Middle East, South Africa, and Australia. The pattern is consistent: most active managers fail to recover their higher costs, and the few who succeed in any given year rarely repeat the feat.
Compounding and long-term returns
The S&P 500's 10.51% average annual return since 1957 is a historical figure, not a guarantee. But it illustrates a deeper truth: staying invested and letting returns compound is often more powerful than trying to time the market or trade frequently. Dollar-cost averaging — investing a fixed amount at regular intervals — helps remove the emotion of market timing and smooths out volatility.
Frequent trading, by contrast, tends to erode returns through transaction costs, taxes, and the compounding of fees. For European investors, dollar-cost averaging (and euro-cost averaging) is a practical way to build a position over time without needing to predict short-term market moves.
The "Index Plus" approach
A practical framework for long-term investors is the "Index Plus" or core-satellite approach. The core — over 80% of the equity portfolio — is held in low-cost passive index funds. The satellite — a small allocation — may include individual stocks the investor understands well, or a modest tilt toward specific themes or sectors.
This approach gives you the low-cost, diversified exposure of passive investing while leaving room for the curiosity and judgement that make investing engaging. If you choose to hold individual stocks, fundamental analysis and diversification remain essential tools.
ETFs for European (and Romanian) investors
European investors benefit from UCITS regulation, which sets strict rules on diversification, leverage, and transparency. UCITS ETFs are ETFs domiciled in Europe and subject to European Union regulation; there are over 2,600 UCITS ETF funds — more than stocks. The largest UCITS equity ETFs include the iShares Core S&P 500 UCITS ETF (Acc) at EUR 82.6 billion and the iShares Core MSCI World UCITS ETF (USD, Acc) at EUR 71.0 billion in market cap.
UCITS ETFs are accessible through most European brokers, often with low minimums and tight bid-ask spreads. Bid, ask, and the spread is a useful concept to understand before placing your first trade. Because the European ETF market remains dominated by passive products, investors have a wide choice of low-cost, regulated vehicles.
Active UCITS ETFs reached EUR 16.3 billion of net inflows in 2024, bringing their total assets under management to EUR 49 billion — a small slice of the European ETF market. The trend is clear: passive products continue to attract the bulk of capital.
Key takeaways
- Passive investing means matching a benchmark rather than trying to beat it, and it is the dominant strategy behind most ETFs.
- Index funds and ETFs offer broad diversification in a single instrument, with no need for stock-picking or a star fund manager.
- Fees compound against you: a difference of a few tenths of a percent in expense ratios can mean tens of thousands of euros less over decades.
- Most active funds underperform their benchmarks over 1, 3, 10, and 15 years, especially after fees.
- Long-term compounding and consistency tend to beat market timing and frequent trading.
- UCITS ETFs give European and Romanian investors regulated, liquid, low-cost access to global markets.
- A core-satellite ("Index Plus") approach lets you capture market returns cheaply while keeping a small allocation for the investments you understand best.
Educational only — not personalised investment advice.