In finance, assets under management (AUM), sometimes called funds under management (FUM), measures the total market value of all the financial assets which a financial institution such as a mutual fund, venture capital firm, or brokerage house manages on behalf of its clients. This metric is very popular within the financial industry and is a sign of size and success of any firm against its competition. The AUM is calculated by different methods.

In the most basic sense, the assets under management metric represents the number of dollars on which a financial firm has the legal right to claim a management fee. This fee is based on the client's contract with the firm and/or fund in question. Therefore, in a given firm the assets under management are not a constant number. AUM is reduced due to redemptions, withdrawals, losses, and other events where investors no longer pay a fee to the manager in question to advise their portfolio. Likewise, AUM can increase when new assets are brought into the firm in question, thereby increasing the fee generating assets the firm manages.