Active management is an investment approach in which a manager makes portfolio decisions to pursue an objective beyond simply tracking a specified market index or benchmark. In a benchmarked mandate, this usually means seeking a higher return while controlling the risk of falling behind. The practical question is whether those decisions add enough value to cover their costs and justify the risks taken.
The SEC's description of an actively managed fund allows for both benchmark outperformance and targeted investment exposure. The objective and permitted decisions belong in the investment mandate; “active” alone does not specify either.
Who makes the decisions?
An active process can be discretionary or systematic. A discretionary manager might overweight a company after analysing its business and valuation. A systematic manager might use a model to rank securities, then choose holdings subject to risk and trading constraints. People still choose a systematic strategy's data, signals, objective and limits. Automation does not make the objective passive. These are both active approaches in CFA Institute's classification.
Conversely, passive management is organised around tracking a specified benchmark. An index fund can trade to accommodate cash flows, index changes and implementation needs. Some use representative sampling rather than holding every constituent. The distinction concerns the investment objective and the reason for departing from benchmark holdings, rather than whether any trades occur. Investor.gov's index-fund guide describes these tracking approaches.
For a fully invested portfolio and benchmark portfolio measured on the same asset universe and capital basis, the active weight in asset is
where and are their respective portfolio weights. An overweight is financed by an underweight elsewhere. These are relative positions: underweighting a stock need not mean shorting it. Security selection, sector allocation and market exposure can all create active decisions.
A gross win that costs more than it earns
Consider one common period with USD 100 initial capital, no external deposits or withdrawals, and hypothetical total returns. The active account earns 8% before the stipulated charge. Its benchmark returns 7.5%. At period end, deduct a fixed USD 1 charge from the active account, based on its initial capital. Ignore all other costs and taxes.
Original hypothetical total-return comparison over one common period. The USD 1 charge is fixed by the example, based on initial capital and paid at period end; there are no other costs, taxes or external flows. The benchmark is an index-style calculation, not an investable fund return.
The active account grows to USD 108 before the charge and ends at USD 107 after it. Its net return is
The benchmark calculation ends at USD 107.50. Defining active return as the arithmetic difference between portfolio and benchmark returns gives:
| Comparison with the same 7.5% benchmark | Active return |
|---|---|
| Gross: 8% minus 7.5% | +0.5 percentage points |
| Net: 7% minus 7.5% | −0.5 percentage points |
The charge exceeds the gross dollar advantage. This is a stipulated cash-charge illustration, not a general formula for accruing fund fees. Real fee schedules specify their own asset basis, timing and treatment of performance fees. Transaction costs and other expenses also require care: costs already included in a reported return must not be deducted again.
What the result establishes
This account underperformed its stated comparator after the charge in this period. That observation alone does not establish that the manager lacks skill, just as the gross outperformance does not establish that the manager has skill.
A useful evaluation fixes the benchmark in advance, checks that it fits the mandate, and compares returns over the same dates, currency and distribution basis. An index return and an investor's return from an index fund can differ because implementation has costs. A portfolio's factor exposures can also explain part of an apparent advantage over an unsuitable comparator.
Risk matters alongside the return difference. Tracking error measures the variability of benchmark-relative returns; it is not the single-period shortfall shown above. Assessing persistent skill requires a longer, appropriately analysed record, attribution and attention to estimation uncertainty. Raw active return is not automatically risk-adjusted alpha. CFA Institute's analysis of active portfolio management develops this benchmark-relative return-and-risk framework.
To move from these ideas to constructing the positions, Mean-Variance Optimisation derives active weights and the effect of constraints (membership for the full lesson; public preview available).
Sources
- SEC Investor.gov: Active Fund or Actively Managed Fund — fund objectives, manager decisions and costs.
- CFA Institute: Active Equity Investing: Strategies (2026), public introduction and summary — discretionary and systematic approaches.
- CFA Institute: Analysis of Active Portfolio Management (2026), public introduction and summary — active weights, benchmark-relative return and risk.
- SEC Investor.gov: Index Funds — tracking objectives, sampling and implementation costs.
- Qian, Hua and Sorensen, Quantitative Equity Portfolio Management: Modern Techniques and Applications, Chapman & Hall/CRC, 2007, Section 2.2.4, pp. 34–35 — active weights and active mean–variance optimisation.