GlossaryAUMFund sizeNet assetsTotal net assets

Assets under management (AUM)

Assets under management is the total market value of the assets a fund holds, net of liabilities, reported either for the whole fund or for a single share class.

Definition

Assets under management (AUM), also called fund size or total net assets, is the value of everything a fund owns (securities, cash, derivatives at market value) minus what it owes. Fund houses publish it on the factsheet as of a given date, in the fund's base currency. A fund with several share classes typically reports both a fund-level AUM and a per-class figure.

Why it matters

Fund size affects liquidity, cost efficiency and viability. Very small funds can carry proportionally higher fixed costs and are more likely to be merged or closed; very large funds in narrow markets can find it harder to trade. For ETFs, AUM is also a rough proxy for secondary-market liquidity. Screeners commonly use minimum AUM thresholds, and client reports show it as a basic fact.

In the API

AUM appears in keyFacts.aum and again in headlineMetrics.aum. Values are numeric, in the currency given by keyFacts.currency, as of dataAsOf. Example values:

json
{
  "keyFacts": { "aum": 78500000000, "currency": "USD" },
  "headlineMetrics": { "aum": 78500000000 },
  "dataAsOf": "2026-07-31"
}

Common pitfalls

Three things trip up comparisons. First, currency: convert before ranking funds with different base currencies. Second, scope: some documents report share-class assets, others fund-level or even umbrella-level totals, so check what the factsheet states. Third, date: AUM moves daily with flows and market prices, so always display dataAsOf. Manager-level AUM (a firm's total) is a different figure altogether. See NAV and the fund screener use case.