What Is AAUM in Mutual Funds, and How Is It Calculated?

AAUM in mutual funds is average assets under management: the average size of a fund across a month rather than its size on one day. SEBI's calculation instruction, reproduced in the Master Circular for Mutual Funds dated 20 March 2026 (read on 19 September 2026), is precise about it. The AAUM of a mutual fund "shall be the aggregate of the daily AUM of the Mutual Fund over calendar days in the relevant month irrespective of the date of allotment/maturity of the scheme", while net AUM takes "the AUM as on the last calendar day of each month". Two different numbers, sitting side by side in the same monthly disclosure, and they routinely disagree. Knowing which one a fact sheet or a headline is quoting is the whole point of reading the column header.

What is AAUM in mutual funds, and how do you calculate it?

Two texts in the master circular say it between them. The Instructions for Calculating AUM give the numerator: the AAUM "shall be the aggregate of the daily AUM of the Mutual Fund over calendar days in the relevant month". The note to column 9 of the disclosure format gives the operation: "AAUM is the average of the daily AUM of the Mutual Fund for the month". So you add up the fund's AUM for every calendar day of the month and divide by the number of days in that month. The instruction is deliberate on two points. It says calendar days, not business days, so weekends and holidays carry the previous day's figure into the average. And it says the averaging runs "irrespective of the date of allotment/maturity of the scheme", so a scheme launched mid-month is averaged across the whole month rather than only the days it existed.

Net AUM is the simpler idea and carries one carve-out of its own: for liquid funds, purchases on the first day of the next month are not counted in the current month's net AUM.

Why does AAUM differ from the month-end AUM?

Because money moves inside the month. AMFI's August 2026 report shows the two columns pulling in opposite directions across categories, which is the cleanest illustration of the difference:

Debt and hybrid schemes ran a higher average than their month-end closing figure in August 2026, and equity schemes ran a lower one. The report states both numbers; it does not state why either moved, and neither does this page.

Where this bites a reader is in comparisons. A scheme size quoted as AAUM and another quoted as month-end AUM are not like for like, and the gap widens for categories with heavy month-end flows, which is why the AMFI format prints them as separate columns rather than one "size" field.

What AAUM disclosures must an AMC make?

Paragraph 6.6 of the master circular splits this in two. Paragraph 6.6.1 says that whenever an AMC discloses the AUM of its schemes it must provide a bifurcation by category, for example debt, equity, hybrid or lifecycle, and the geographical distribution of AUM as a percentage from the top 5 cities, the next 10, the next 20, the next 75 and others, on its own website and to AMFI, which publishes industry-wide figures.

Paragraph 6.6.2 then sets the monthly AAUM list. AMCs disclose the following on their websites in spreadsheet format and furnish the same to AMFI within 7 working days from the end of the month:

• Monthly AAUM from different categories of schemes, such as equity schemes and debt schemes.
• Contribution to monthly AAUM from B-30 cities, meaning those outside the top 30 identified by AMFI, and from T-30 cities.
• Contribution from the sponsor and its associates, and separately from entities other than the sponsor and its associates.
• Contribution by type of investor, such as retail and corporate, across scheme types including equity, debt and ETFs.
• Monthly AAUM garnered through sponsor-group and non-sponsor-group distributors.
• State-wise and union-territory-wise contribution to monthly AAUM.

Paragraph 6.6.3 requires mutual-fund-wise and consolidated data on the same parameters on AMFI's website, in the prescribed Format No. 4D. That is why the industry numbers above are readable at all.

Where does AAUM sit against the other mutual fund disclosures?

AAUM answers "how big was this fund, on average, last month". It does not tell you what the fund held. That is the monthly scheme portfolio, published within 10 calendar days of month-end under paragraph 6.1.1 of the same master circular; see what a monthly portfolio disclosure is and how to find which mutual funds are buying a stock. The summary document that pulls size, holdings and costs onto one page is the mutual fund factsheet, and the full calendar of what is due when is in mutual fund disclosure timelines.

One caution on cost. The expense ratio is a separate measurement with its own base in the SEBI (Mutual Funds) Regulations, 1996, which this page has not read, so do not assume it is computed on the monthly AAUM published under paragraph 6.6.2; see what the total expense ratio is.

Flock reads AMFI and scheme portfolio disclosures from their published sources and keeps every number stamped with the period it belongs to, so an AAUM figure on this site carries the month it averaged. What a fund's size means for your money is your call to make. This is not investment advice.