Why Size Doesn’t Kill Mutual Fund Performance

Key Takeaways

• A large AUM (Assets Under Management) is often a sign of investor trust and a proven track record, not a signal of impending failure.
• While “liquidity” is a concern for small-cap funds, large-cap and multi-cap funds can manage massive sizes due to the depth of the Indian stock market.
• Institutional systems, advanced technology, and experienced fund management teams help mitigate the “size drag.”
• Investors should focus on risk-adjusted returns and fund consistency rather than just the total corpus of the fund.
• The relationship of mutual fund asset size vs performance is nuanced and depends heavily on the category of the fund.

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Introduction

In the world of Indian investing, there is a persistent myth that haunts many retail investors: “The fund has become too big; it won’t give good returns anymore.” You might have heard this at a social gathering or read it on a forum.

The idea is that once a mutual fund manages thousands of crores, it becomes a “clumsy giant” that can’t move fast enough to beat the market.

However, if we look at the data of the Indian mutual fund industry over the last decade, the reality is quite different. Many of India’s largest equity funds have continued to outperform their benchmarks year after year. Being big isn’t a death sentence for returns.

In fact, in many cases, size brings stability, lower costs, and better access to information. Let’s dive deep into why mutual fund asset size vs performance isn’t the “Goliath” problem people think it is.

Understanding AUM: What is it?

Before we talk about performance, let’s clarify what “size” means. In mutual fund parlance, size is referred to as AUM (Assets Under Management). This is the total market value of all the investments held by the mutual fund scheme.

As per the data released by the Association of Mutual Funds in India (AMFI), the Indian Mutual Fund Industry’s AUM surged 12% to touch Rs. 73.73 lakh crore in FY26.

When a fund performs well, more investors want to join in. As more money flows in and the value of existing stocks goes up, the AUM grows. Therefore, a large AUM is usually a “certificate of merit” from the market. It means the fund manager has done something right for a long time.

The “Size Penalty” Myth

The logic behind the fear of large AUMs usually boils down to three points:

1. The Impact Cost: A large fund buying a huge chunk of a small company might drive the price up before they finish buying.
2. Lack of Agility: Large funds can’t “exit” a stock quickly without crashing the price.
3. Limited Universe: A massive fund can’t invest in tiny “multibagger” companies because a 10-crore investment won’t move the needle for a 50,000-crore fund.

While these points have some merit in specific sectors like Small Cap funds, they are often exaggerated when applied to the broader market. Here is why size doesn’t necessarily kill performance.

1. The Depth of the Indian Market is Growing

A decade ago, the Indian stock market was relatively “thin.” Trading volumes were lower, and only a few stocks were truly liquid. Today, India is one of the top performing and most liquid markets globally.

For a Large Cap fund, having an AUM of ₹40,000 crore is no longer a burden. The large cap funds of Nippon India, ICICI Prudential and SBI are already part of the ₹50,000-crore assets under management (AUM) club. The top 100 companies in India (the Large Cap universe) have massive daily trading volumes.

A fund manager can buy or sell hundreds of crores worth of HDFC Bank or Reliance Industries without causing a ripple in the share price. As the Indian economy grows toward a $5 trillion and $7 trillion target, the “capacity” of our markets to absorb large fund sizes increases. This shifts the needle in the debate of mutual fund asset size vs performance.

2. Institutional Access and Better Research

When a mutual fund becomes large, it becomes a “whale” in the eyes of corporate India. Large fund houses have access to:

• Direct Access to Top Management: CEOs and CFOs of India’s biggest companies are more likely to meet with a fund manager who holds 5% of their company than one who holds 0.01%. This provides better qualitative insights into business strategy.
• Superior Research Teams: Larger AUM usually means more revenue for the AMC (Asset Management Company), which allows them to hire the best analysts and use the most expensive data terminals (like Bloomberg).
• Better Systems: Large funds invest heavily in algorithmic trading and execution platforms that minimize “impact cost” by breaking large orders into tiny pieces executed over hours or days.

3. Expense Ratios Actually Go Down

Here is a tangible benefit for the investor: Economies of Scale. The SEBI (Securities and Exchange Board of India) has a “slab-based” structure for Total Expense Ratios (TER). As the AUM of a fund grows, the percentage the AMC can charge as a fee must decrease.

For example, a small fund might charge you 2.2% in expenses, while a massive fund might charge only 1.7% or less. That 0.5% difference stays in your pocket and compounds over 20 years.

In the long run, the lower cost of a large fund can actually compensate for any slight loss in agility, proving that mutual fund asset size vs performance can favour the larger player through cost-efficiency.

4. Stability During Market Crashes

Small funds often face “concentration risk.” If a few investors pull out large sums of money during a market panic, the small fund manager might be forced to sell their best stocks to pay the investors back.

A large fund, however, has a much broader investor base. On any given day, while some people are selling, others are starting new SIPs. This “net flow” is often more stable in large, well-established funds. The fund manager isn’t forced into “fire sales,” allowing the fund to navigate volatile periods with much more grace than a tiny, volatile scheme.

5. Diversification Without Dilution

Critics argue that large funds “over-diversify,” owning 80–100 stocks, which makes them “closet index funds.” While some funds do this, many large funds maintain a “conviction-heavy” portfolio.

Modern portfolio theory suggests that you get most of the benefits of diversification with 30–40 stocks. Even a ₹60,000 crore fund can comfortably hold 40–50 large-cap stocks without owning too much of any single company.

A typical example is Motilal Oswal Midcap fund with an AUM of Rs. 31046.66 Crores. Though this fund is currently holding a total of 27 stocks, the maximum holding percentage of a single stock is 7.44%. The idea that size forces a manager to buy “junk” stocks just to fill the portfolio is largely a misconception in the Indian context, especially in the Large and Mid-cap categories.

When Does Size Actually Matter?

To be fair and transparent, size isn’t completely irrelevant. It depends on where the money is being invested.

Small Cap Funds

This is the one area where size can be a challenge. Small-cap companies have low liquidity. If a Small Cap fund grows to ₹30,000 crore, it becomes very difficult for the manager to deploy cash into tiny companies without skyrocketing the stock prices.

This is why you often see large Small Cap funds “stop” taking lump-sum investments—they are protecting their existing investors. A relatable example is Nippon India small cap fund that stopped taking lump-sum investments in July 2023.

Large and Flexi Cap Funds

For these categories, size is rarely an issue. The “Flexi Cap” category, in particular, allows managers to move money into Large Caps if the fund size becomes too big for Mid Caps. If we take the case of 44 flexi cap funds, currently 37 of them hold more than 50% of their portfolio in large cap stocks.

It is to be noted that the average exposure amounts to 64% large cap, 19% mid cap and 18% small cap. This flexibility effectively solves the mutual fund asset size vs performance dilemma.

Examples of Performance Staying Strong

Look at some of the “Bluechip” or “Value” funds in India that have been around for 20+ years. Many of these started with just a few hundred crores and now manage over ₹40,000 or ₹50,000 crore. If you track their 10-year or 15-year CAGR (Compound Annual Growth Rate), they have consistently beaten their benchmarks.

Their size allowed them to survive the 2008 crash, the 2013 taper tantrum, and the 2020 pandemic. The “experience” of the fund house and the “process” they follow are far more important than the AUM number.

How Investors Should Evaluate a Fund

Instead of looking at the AUM, investors should look at these three factors:

1. Fund Manager Tenure: Has the same person been managing the “large” fund for a long time? Consistency in leadership is key.
2. Capture Ratio: How much of the market’s upside does the fund catch, and how much of the downside does it protect? Large funds often excel at downside protection.
3. Portfolio Turnover: Is the manager trading too much? A large fund should ideally have a lower turnover, indicating a “buy and hold” strategy which is more sustainable for large sizes.

The debate of mutual fund asset size vs performance should always be secondary to the fund’s investment philosophy and the quality of its underlying holdings.

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Conclusion

Size is a double-edged sword, but in the evolving Indian market, the “sharp” edge is usually working in the investor’s favour. While a massive AUM might make a fund less “nimble” in the small-cap space, for most investors in Large, Mid, and Flexi Cap funds, a large AUM is a sign of a healthy, trusted, and cost-effective investment vehicle.

Don’t fear the “Big Fund.” A large corpus often brings with it institutional discipline, lower costs, and the best analytical minds in the country. When it comes to mutual fund asset size vs performance, remember that a large ship might turn slowly, but it is also much harder to sink in a storm. Focus on the long-term track record, the fund manager’s DNA, and your own financial goals.