What are assets under management (AUM)?

Assets under management can be reported for a fund, portfolio or whole firm. BlackRock’s glossary defines the measure in terms of the market value of assets managed on investors’ behalf.

AUM changes when investments rise or fall in value and when investors add or withdraw money. An increase is therefore not necessarily new customer money; interpreting ETF flows also requires separating price effects. Comparisons should use consistent dates and coverage.

Example: a $6 million increase, but $1 million net inflow

Suppose a hypothetical portfolio starts with $100 million, gains $5 million from market movements, receives $2 million in deposits and pays out $1 million in withdrawals. Ignoring other effects, ending AUM is 100 + 5 + 2 − 1 = $106 million. Net investor inflow is only $1 million, rather than the entire $6 million increase.

The same distinction matters when reading about BlackRock’s scale in Larry Fink’s career: client assets do not become the executive’s personal property. AUM alone does not establish profitability or successful investment performance.