The same companies can give you different returns.
Owning a market means participating in underlying businesses or debt claims. Customers can generate business profits; borrowers owe contractual payments. The price paid, future cash flows and valuation changes determine the investor’s result, reduced by costs. The fund is the route to those claims.
Starting capital: each full bar = €10,000. A is solid; B is hatched.
Market-value proportions
A · 80% · €8,000↓ at +10%+€800
B · 20% · €2,000↓ at −10%−€200
Combined gain: +€600 / €10,000 = 6%
Equal amounts
A · 50% · €5,000↓ at +10%+€500
B · 50% · €5,000↓ at −10%−€500
Combined gain: €0 / €10,000 = 0%
Names alone do not establish market exposure: proportions change the result. Domestic shares, global shares and government bonds have different markets and indexes, with different selection and weighting rules.
An index fund aims to capture its chosen market through a real portfolio, subject to costs and implementation limits. You choose exposure and risk without having to forecast next year’s winning company.
Weights, currency and income
Market weights give 80% × 10% + 20% × (−10%) = 6%; equal amounts give 50% × 10% + 50% × (−10%) = 0%. Multiply each starting weight by that company’s total return, then add the contributions.
A price-only index excludes payments included in a total-return index. Different currencies or income measures can manufacture an apparent advantage without investment skill.
Who is making the forecasts?
A passive fund follows index rules; an active manager uses judgement within a mandate, often to beat a benchmark. Either can use an ETF or another fund format.
An active manager may hold companies for years. Repeatedly switching index funds to catch winning countries or industries makes active forecasts. Trading frequency does not define the distinction.
Passive still needs implementation
Index funds handle cash flows and index changes. Narrow industry indexes can be concentrated; passive does not establish diversification or suitability. Ask whether the exposure serves its purpose without repeated choices about the next winner.
The active group still belongs to the market.
In Sharpe’s defined-market framework, passive investors hold market-value proportions. The remaining investors collectively own the remainder. Both groups earn the market return before costs: an average weighted by money invested, not an identical result for every investor.
Higher costs leave a group with less after costs. This accounting identity does not predict the market’s future return. Concentrating in one company or paying an extra charge creates no additional economic payment to compensate you.
The boundary of this arithmetic
Together the groups own the defined market. This concerns all its investors, not automatically a study’s selected professional funds.
It requires neither perfectly correct prices nor absence of skill. Individual active results differ; every active fund need not lose to every index fund. Finding an approach that will justify extra costs is a separate task, unsettled by past success alone.
A higher charge has to be earned back.
Each full bar = the same €700 gross gain, not the whole account
A: €700 gain → deduct €30
Solid: €670 keptHatched: €30 costs
€10,000 + €670 → €10,670 · 6.7% after costs
B: €700 gain → deduct €150
Solid: €550 keptHatched: €150 costs
€10,000 + €550 → €10,550 · 5.5% after costs
B needs an extra gain just to finish level. Its fee is no evidence that it can earn the difference.
Calculate the gap; check real charges
The €150 − €30 = €120 gap is 1.2% of starting capital: 1.2 percentage points of extra before-cost return to finish level here.
Actual charges can depend on values, transactions or deduction dates, and leave less for future growth. Check fund, account and dealing charges; this is no universal fee formula. Index funds also incur expenses and tracking differences: the index is a reference, not a promised account return.
Choose the benchmark before seeing the result.
Match intended exposure, period, currency, income and cost scope. A share-only index gives a limited comparison for shares, bonds and cash: defensive holdings can help in falling markets and lag a share rally.
Check the spending goal separately. Accurate tracking of a falling market may still leave a bill short.
Contributions change the question
Separate strategy returns from personal cash-flow experience when you add or withdraw money. A suitable benchmark assesses implementation; the amount, timing and risk must also fit the spending supported.