Mutual Fund Overlap: How to Evaluate Mutual Fund Overlap in Your Portfolio?

Mutual fund overlap is the extent to which two or more funds you hold are invested in the same underlying stocks. It occurs when the MF schemes you hold invest in the same underlying securities. For example, if your large-cap fund and your flexi-cap fund both hold Reliance, HDFC Bank, and Infosys in their top 10, you're not diversified; you're doubling down on the same positions while paying two separate expense ratios.

The keyword is securities, not funds. You can own five different fund names, five different brand labels, and still own essentially the same basket of 30 stocks. The diversification was an illusion created by the packaging.

Why this Matters more than it looks

Diversification's whole job is to make sure that when one part of your portfolio falls, another part holds up, so your total doesn't swing as violently. Overlap quietly cancels that out.

When the same stock appears across multiple funds in your portfolio, a single bad quarter from that company can pull down everything you own at the same time. If Reliance is 8% of Fund A, 7% of Fund B, and 6% of Fund C, and you've split your money evenly across them, your true exposure to Reliance is far larger than you'd ever knowingly take in a single stock. The risk you thought you'd spread out is actually concentrated.

There's a second cost that's easy to ignore. Each fund charges an expense ratio, an annual fee, taken as a percentage of your investment, for managing the fund. If two funds hold near-identical portfolios, you're paying two management fees for one underlying portfolio. You're paying for active stock-picking that, in aggregate, isn't picking different stocks.

Put bluntly: high overlap gives you the downsides of concentration and the cost structure of diversification, the worst of both.

How Overlap is Actually Calculated

Most beginners assume overlap means "how many stocks two funds have in common." That's the naive version, and it's misleading. The number that matters is the overlap by portfolio weight, not by stock count.

Here's the difference. Two funds might share 40 stock names, but if those shared names are tiny 0.2% positions in each fund, the real overlap is small. Conversely, two funds might share just 12 names, but if those 12 are each fund's biggest holdings, the real overlap is huge.

Proper overlap is calculated by taking the common weights of each stock across the fund portfolios, the overlap by portfolio weight between each pair of funds, using the latest available monthly fund portfolios. For each stock held by both funds, you take the smaller of the two weights (that's the portion genuinely duplicated), and you add those up across all common stocks. That sum is your overlap percentage.

Let me show it with numbers, because this is the part worth understanding properly.

Example 1: Two Funds, Worked out by Weight

Suppose you hold Fund A and Fund B. Here are their top overlapping holdings and the weight each stock has in each fund:

So the overlap between Fund A and Fund B is 27%, meaning a little over a quarter of these two funds is the same exposure. Roughly 73% of each fund is doing something different from the other.

Why take the smaller weight each time? Because that's the portion that's genuinely duplicated. If Fund A holds 9% HDFC Bank and Fund B holds 8%, the overlapping, redundant chunk is the 8% they share the extra 1% in Fund A is unique to it. Counting the full 9% would overstate the duplication.

This is exactly what overlap tools do under the hood. They show overlapping stocks, the overlap percentage, and each stock's weight contribution, so you can make a clean decision.

What counts as "too much"? Reading the number

A single overlap percentage is meaningless without context. The same 50% means very different things depending on what kinds of funds you're comparing. A widely used banding looks like this:

One common banding categorises overlap as Low (0–20%), Moderate (20–60%), and High (60%+), to help investors quickly assess risk exposure.

But, and this is the analytical part beginners skip- you have to adjust the threshold for the category. Some overlap is structurally unavoidable, and penalising it would be a mistake.

Consider two large-cap funds. By regulation, large-cap funds are limited to the top 100 companies and must invest at least 80% there, so some overlap between them is unavoidable. Two large-cap funds sharing 50% of their portfolio isn't a red flag; it's the nature of the category. In practice, overlaps between large-cap funds in India typically range from about 35% to 55%.

Now consider a large-cap fund and a thematic or sectoral fund. These are supposed to be doing completely different things. Sectoral and thematic funds have thousands of stocks to choose from, but often cluster into the same popular names, and that clustering is the real risk. If your "diversifying" thematic fund overlaps 50% with your large-cap fund, that's a genuine problem, because you paid for differentiation and didn't get it.

The analytical rule of thumb: the more different two funds claim to be, the lower the overlap you should tolerate. Two large caps at 45% is fine. A large-cap and a mid-cap at 45% is suspicious. A large-cap and a sector fund at 45% is a failure of the thing you bought it for.

How to Evaluate Overlap in your own Portfolio

Here's the actual process an informed investor runs:

1. List every equity fund you hold. Overlap analysis is meaningful for equity (and equity-heavy hybrid) funds; overlap tools cover pure equity funds, as overlaps are an important consideration for these funds alone. Debt funds and equity funds don't meaningfully overlap. 
2. Run them through a free overlap tool. Free options for Indian investors include Dezerv, Advisorkhoj and others. Most let you enter up to 3–5 schemes, identify the common stocks, calculate the overlap percentage, and visualise which fund pairs overlap most.
3. Read overlap by weight, not stock count. Ignore "they share 38 stocks" headlines. Look at the weighted overlap percentage and the top overlapping holdings.
4. Judge each pair against its category. Apply the adjusted thresholds above. High overlap between two same-category funds is expected; high overlap between funds that are supposed to differ is the real signal.
5. Don't treat overlap as the only metric. It's the starting point, not the whole analysis. As one framework puts it, a full portfolio review should cover four dimensions: overlap across schemes, asset allocation versus your target, performance against benchmark, and cost efficiency through expense ratios. Overlap is the starting point because you can't assess diversification without it.

The Common Confusion: Overlap is not the Same as a Bad Fund

This trips people up constantly. A fund with high overlap is not a bad fund. The two funds in your portfolio might both be excellent, well-managed, top-rated schemes. Overlap says nothing about the quality of either fund; it only says something about the relationship between them in your portfolio.

So the fix for high overlap is never "this is a bad fund, sell it." It's "these two funds are redundant together, so I only need one of them, and I should use the freed-up money for something genuinely different." You're not judging the fund. You're judging the combination.

A related confusion: people see overlap and assume the solution is to own fewer funds. Not necessarily. The solution is to own funds with low overlap with each other. You could own seven funds with low mutual overlap and be better diversified than someone with three funds at 80% overlap.

A Useful Change Coming: SEBI is Making Overlap Visible

Until now, checking for overlap meant doing this work yourself using a third-party tool because fund houses didn't publish it. That's changing.

From 26 August 2026, SEBI requires fund houses to publish monthly overlap reports between their schemes, so you'll finally see how much two funds from the same AMC share. It also caps overlap at 50% for sectoral and thematic funds with other equity schemes from the same fund house, while large-cap funds are exempt because their top-100 mandate makes some overlap unavoidable.

This is worth knowing because it tells you which overlap regulators themselves consider dangerous, the thematic-and-sectoral kind, exactly the funds investors most often buy, believing they're adding diversification.

Things to Keep in Mind

• Overlap data is a monthly snapshot. Tools use the latest disclosed portfolios, and fund managers change holdings over time. Today's 30% overlap could be 40% next quarter. Recheck periodically rather than treating a single reading as permanent.
• Some overlap is fine and even healthy. Zero overlap across your whole portfolio is neither realistic nor a goal. The aim is to avoid unintended, expensive duplication, not to chase a number to zero.
• Don't churn on overlap alone. Selling a fund can trigger exit loads and capital gains tax. Use overlap to inform future allocation and gradual rebalancing, not to dump funds reactively. A high overlap reading is a reason to investigate, not an automatic sell order.
• The fee angle is the quiet one. Two overlapping active funds mean two expense ratios on one portfolio. If two funds are nearly identical, ask whether you'd be better served by one of them or by a low-cost index fund covering the same ground.

Conclusion

Mutual fund overlap is the gap between how diversified your portfolio looks (many fund names) and how diversified it actually is (the underlying stocks). Measured properly, by portfolio weight, judged against each fund's category, it tells you whether your funds are genuinely working as a team or just buying the same companies in parallel while charging you several times for it.

The goal isn't to fear overlap or eliminate it. It's to make sure every fund you hold is earning its place by giving you exposure that the others don't. Run the numbers once, read them with category context, and you'll never again mistake more funds for more diversification.