Explain the arithmetic of active management and weigh the evidence on fund performance and costs.
William Sharpe (1991) made an argument that needs no data. The market return is the weighted average of all investors' returns. Passive investors earn the market return before costs. Therefore active investors, as a group, must also earn the market return before costs. Because active management costs more, the average actively managed dollar must underperform the average passively managed dollar after costs. This holds in every market, efficient or not.
Scorecards that track funds against their benchmarks (the SPIVA reports from S&P Dow Jones Indices are the best known) consistently find that a majority of active equity funds underperform over 10 years or more, in both the US and Canada, and the proportion rises with the length of the period. Look up the latest report for current figures. Funds that outperform in one period are no more likely than chance to outperform in the next.
$100,000 invested for 30 years:
| Net annual return | Ending value |
|---|---|
| 7% (no fee) | $761,226 |
| 6.5% (0.5% fee) | $661,437 |
| 5% (2% fee) | $432,194 |
A 2% annual fee consumes 43% of the ending wealth. Fees are the most reliable predictor of a fund's future relative performance.
Less-researched markets such as small caps, emerging markets and some bond sectors; investors with constraints an index cannot meet; and managers with a real informational or structural edge. Even there, the average result after fees is weak, and identifying winners in advance is the hard part.
An index fund holds all or a sample of the securities in an index at their index weights. Quality is judged by tracking difference (fund return minus index return, mostly the fee) and tracking error (how variable that gap is). Securities lending income can offset part of the fee.
Market-cap weighting holds more of whatever has risen most, so it becomes concentrated when a few companies dominate. Index inclusion and deletion create predictable trading that others exploit. Passive investors rely on active investors to set prices. Large index managers hold significant voting power across most public companies.
Build the core of a portfolio from low-cost broad index funds. If you want active positions, limit them to a defined satellite, measure them against a fair benchmark after costs, and review the record honestly.
(1) Planning: write the IPS and capital market expectations. (2) Execution: choose the asset mix and the funds or securities, and trade efficiently. (3) Feedback: monitor, rebalance, measure performance and revise the plan when circumstances change.
Active share measures how much a fund's holdings differ from its benchmark's, from 0% (identical) to 100% (no overlap). Research by Cremers and Petajisto labelled funds with active share below about 60% as closet indexers: charging active fees for portfolios that mostly mirror the index.
A fund with an active share of 30% charges 1.0%; an index fund costs 0.05%. Seventy percent of the fund is effectively the index, so the investor pays 0.95 percentage points extra for the 30% that differs, an effective fee of 0.95 / 0.30 = 3.2% on the active portion. That active slice must outperform by more than 3% a year just to break even.
An index fund returned 9.82% in a year when its index returned 9.90%. Its tracking difference is -0.08 points, close to its fee. A tracking difference much worse than the fee points to costs or poor management; one better than the fee often reflects securities lending income.
Market-cap weighting is cheap to run and self-rebalancing. Equal weighting gives more weight to smaller companies and requires regular rebalancing, raising turnover and costs. Fundamental weighting (by sales, earnings or dividends) tilts toward value. Each alternative is a factor bet as much as an index (Module 6).
Some platforms let investors hold the individual stocks of an index instead of a fund. The main benefit is tax-loss harvesting: selling individual losers to realize tax losses while keeping index-like exposure. The benefits are largest for high-income investors in taxable accounts making new contributions; the costs are complexity and, in some cases, higher fees.
Beyond the expense ratio: trading costs inside the fund (higher for high-turnover active funds), cash drag, taxes on distributions and, for advised accounts, the advice fee itself. Compare total costs in dollars.
For most investors, a broad, low-cost index core captures the market return reliably. Active choices make sense when the investor can identify a genuine edge, pay a fee small enough to leave something after costs, and stick with the manager through inevitable periods of underperformance.
Compare one actively managed mutual fund with an index ETF in the same category: management expense ratio, 10-year return, volatility and the fund's benchmark. Compute the dollar cost of the fee difference on $50,000 over 25 years at a 6% gross return.
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