Assets under management measures the value managed under a stated reporting boundary. Reconcile investment gains, client flows and an explicitly chosen fee base.
Assets under management
Assets under management (AUM) is the aggregate value of the investment portfolios a manager manages, measured at a stated time under a stated inclusion and valuation convention. It describes the scale of the managed business. A rise in AUM can come from client contributions as well as investment gains, so it cannot by itself establish investment performance.
The qualification matters. A figure for one fund, a strategy and an entire management group can cover different assets. A regulatory AUM measure, an investor-capital measure and a contractual fee base can also differ even when they refer to the same business.
Read the boundary before the number
A useful AUM figure comes with four pieces of context:
Scope: which accounts, funds and affiliated managers are included; whether discretionary and other managed assets are combined; and how overlapping holdings or nested funds are treated.
Valuation: the date and time of the marks, the pricing method, the reporting currency and any currency-conversion convention.
Balance convention: whether the figure measures gross assets, net asset value, committed capital or another explicitly defined quantity.
Movements: how subscriptions, redemptions, acquired mandates and changes in reporting scope enter the comparison over time.
Do not add a fund's holdings to the value of the same fund units held by an account and call that total unique investor capital. An aggregation must say what it is counting. Nor does “under management” imply that the manager owns the client assets or that the assets sit on the manager's own corporate balance sheet.
There are formal definitions for particular purposes. For example, U.S. Form ADV regulatory AUM includes qualifying securities portfolios receiving continuous and regular supervisory or management services. Its instructions prohibit deducting outstanding indebtedness and accrued unpaid liabilities; they also include uncalled commitments for private funds. This is a specific regulatory convention, not a universal definition of investor wealth or a fee denominator. See the SEC instructions, Part 1A, Instruction 5.b, for the inclusion and valuation rules.
A closing balance does not explain its own growth
Consider a synthetic manager with two nonoverlapping, unlevered portfolios in USD. At the opening valuation, portfolio A is worth USD 100 million and portfolio B USD 50 million. The reporting boundary remains these two portfolios for the full year. There are no liabilities, foreign-currency effects, expenses or external flows until the final instant.
Portfolio A earns USD 5 million during the year; portfolio B loses USD 1 million. Their combined value immediately before the final client flow is therefore USD 154 million. A client then contributes USD 10 million at period end, after the year's investment result, bringing closing AUM to USD 164 million. The contribution remains managed cash at that valuation.
Two nonoverlapping portfolios open at USD 100 million and USD 50 million. Gains of plus USD 5 million and minus USD 1 million bring AUM to USD 154 million. A final client contribution of USD 10 million gives closing AUM of USD 164 million. AUM growth is 9.33 percent while investment return is 2.67 percent.
Original synthetic annual ledger in USD millions. The contribution arrives after the investment gain; the reporting boundary is fixed. Percentages are rounded to two decimal places. The separate fee illustration below is excluded from this ledger.
For this fixed boundary, the reconciliation is
A1=A0+G+F,
where A0 and A1 are opening and closing AUM, G is investment gain, and F is external contributions less withdrawals. In USD millions, 164=150+4+10.
The growth of the reported balance is
A0A1−A0=15014≈9.33%.
The investment return over this year is instead
R=A0A1−F−A0=1504≈2.67%.
Subtracting the end flow works here because none of it was invested during the return period. This equals the time-weighted return for this example. With flows during the period, their timing matters: performance measurement requires an appropriate cash-flow treatment, such as valuing and linking subperiod returns around external flows. Simply subtracting all flows and dividing by opening AUM is not a general time-weighted-return formula. Elton et al., Chapter 26, explains why equal investment performance can coexist with different ending fund values.
A transfer between these two portfolios would be internal to the manager's stated boundary and would not increase aggregate AUM. Conversely, adding a newly acquired mandate to the reporting scope could increase reported AUM without either an investment gain or a contribution to the original portfolios. Reconcile scope changes separately rather than hiding them in performance.
“One percent of AUM” still needs a base
For a separate fee illustration, stipulate an annual fee of 1% of opening AUM, payable outside the portfolios. This is a chosen contract for the example, not an industry-wide rule. The annual charge is
0.01×USD 150 million=USD 1.5 million.
Closing AUM of USD 164 million does not change that stipulated opening base. A different agreement could use an average balance, an end balance, tiered rates or other terms, with its own billing frequency and flow adjustments. The SEC's investor bulletin on fees describes asset-based advisory fees and the disclosures to consult. AUM alone is insufficient to reconstruct revenue, and an asset-based fee is different from a fee linked to investment profits.
Scale changes what a strategy must execute
AUM is also a sizing input. Holding a portfolio weight constant while increasing the capital base increases the corresponding dollar position and the order needed to change it. More assets can therefore raise market impact, liquidity demands and the difficulty of implementing a signal. Large AUM does not prove either superior returns or unlimited capacity.
The next useful distinction is capacity analysis: how much capital a particular trading policy can deploy while meeting its execution and performance requirements. Capacity and Market Impact develops participation constraints and capital-dependent execution costs. Its full lesson requires membership; a public preview is available. The capital convention used in such a model must match its position and return denominators, rather than being substituted from an unrelated headline AUM figure.
Sources
Elton, E. J., Gruber, M. J., Brown, S. J. and Goetzmann, W. N. Modern Portfolio Theory and Investment Analysis, 9th edition, Wiley, 2014. Chapter 26, “Evaluation of Portfolio Performance,” pp. 661–662, “Measures of Return.”
U.S. Securities and Exchange Commission. Form ADV instructions, July 2024 version, Part 1A, Instruction 5.b, pp. 20–22. Checked 26 October 2026.
