What is AUM in Mutual Funds? — Does Fund Size Matter?
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AUM (Assets Under Management) shows how much money a fund manages. Learn when a large AUM helps, and when it can actually hurt small and mid cap fund returns.
AUM (Assets Under Management) is the total market value of all the investments a mutual fund holds on behalf of its investors. It's reported in crores and updated regularly as investors add or withdraw money and as the underlying holdings change in value.
Does a Bigger AUM Mean a Better Fund?
It depends entirely on the fund category:
| Fund Category | Effect of Large AUM |
|---|---|
| Large Cap / Index Funds | Neutral to positive — large caps are liquid enough to absorb big AUM without impacting execution |
| Mid Cap Funds | Mixed — very large AUM can force the manager into less-liked stocks just to deploy capital |
| Small Cap Funds | Often negative — small cap stocks have limited float; a bloated fund struggles to buy/sell without moving the price |
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Why This Matters
A small cap fund with ₹500 crore AUM can move in and out of stocks nimbly. The same fund at ₹20,000 crore AUM may be forced to hold larger positions for longer, effectively behaving more like a mid cap fund while still being marketed as "small cap." This is why several AMCs cap or even close small cap fund inflows once AUM crosses a threshold.
Rule of thumb: for large cap and index funds, AUM size is largely irrelevant to performance. For mid and small cap funds, check whether AUM has grown extremely fast recently — it can be an early warning sign of future underperformance.
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