Mutual fund overlap: how to check it across your whole portfolio, and what the number means

Most overlap tools ask you to pick two funds and give you a percentage. That is a start. It is also the wrong unit. You do not hold two funds; you hold six or eleven or seventeen, and the number that affects you is how much of all that money is riding on the same handful of companies.

This guide explains how overlap is measured (SEBI now publishes the formula), where the holdings data comes from, how to extend the check to your whole portfolio in a spreadsheet, and how to read the result. It describes the arithmetic of the choices people then face. It does not tell you what to buy, sell or switch. Corpus is in the process of SEBI registration and, until that is granted, this site is education only.

The formula

Before February 2026 there was no official formula. Most calculators used the minimum-weight method, and SEBI has now written the same method into its scheme categorisation circular, because fund houses have to measure overlap between their own schemes.

For each stock held by both funds, take the smaller of the two weights. Add those up. That sum is the overlap.

(Illustrative weights, not any actual scheme.)

A weight is the stock's market value divided by the scheme's total assets, matched at ISIN level. SEBI's version uses total assets as the denominator, so cash and debt holdings dilute every weight; some tools use equity holdings only, which is one reason two calculators can disagree by a few points on the same pair.

Some tools report something else: the number of stocks the two funds have in common divided by the number of distinct stocks across both. That is a count, not an exposure. Two funds can share 40 of 60 names and still overlap only 25% by weight if the big positions differ. Check which one a tool is giving you before you compare results.

Where the holdings come from

Every fund house has to publish each scheme's full portfolio, with ISINs, as on the last day of the month, within 10 calendar days of month end, on its own website and on AMFI's, as a downloadable spreadsheet. Debt schemes publish fortnightly. If your email is registered, the fund house also sends you a link to the portfolios of the schemes you hold.

So the raw material is public and never more than about six weeks old. An overlap tool is a convenience layer on top of these spreadsheets. If you can use a spreadsheet, you can do the whole-portfolio version yourself, which a two-fund calculator is not built to do.

New from 2026: fund houses also have to publish, every month, the overlap between their own schemes category by category. That page on an AMC's website is worth a look before you add a second fund from the same house.

Running it across your whole portfolio

Six steps. Half an hour the first time, ten minutes after that.

1. From your CAS, list each scheme you hold and its current value. (The guide on reading your CAS covers where to find this.)
2. Download the latest monthly portfolio spreadsheet for each scheme from the fund house's site.
3. In one sheet, for each scheme, multiply each stock's weight by the rupees you hold in that scheme. That gives your rupee exposure to each stock through that fund.
4. Add up by ISIN across all schemes. Sort descending.
5. Divide each total by your overall equity value. That column is your real portfolio, the one the fund names do not show.
6. For sectors, do the same with the sector column the spreadsheet provides.

Two things fall out of this that no pairwise number shows. First, your top ten stocks as a share of everything. Second, which single stock you are most exposed to, and through how many funds. A portfolio of several large cap funds can end up with a single private bank at 8 to 10% of the total, spread across five "different" funds.

You can also build the pairwise matrix from the same sheet (apply the formula above to each pair), but once you have the consolidated view, the pairwise percentages matter less.

Why large cap funds overlap by design

SEBI defines a large cap stock as one of the 100 largest listed companies by average full market capitalisation, on a list AMFI updates every six months. A large cap fund must keep at least 80% of its money in those 100 names. A flexi cap fund must keep at least 65% in equity but may spread it across any market cap, a large and mid cap fund needs 35% in each, a mid cap fund needs 65% in companies ranked 101 to 250, a focused fund may hold at most 30 stocks.

Now look at how concentrated the top of the market is. As of 30 September 2026, the ten largest weights in the Nifty 50 added up to 52.3% of the index, with the largest single stock at 10.4%. In the Nifty 100, the same ten names were 42.4%. (Index constituents are quoted for illustration only and are not recommendatory.) A fund manager with an 80% large cap mandate is choosing from a pool where the big names dominate, so even an actively managed large cap portfolio tends to carry the same large positions as the index.

Put three large cap funds together and the overlap is the category, not the managers. The three-fund question people ask most ("which of my three large caps should I drop") has a first answer that is just arithmetic: by holding three, a large share of your money sits in the same top-100 names through three schemes, each with its own expense ratio. How large that share is, the consolidated sheet will tell you. Whether that is a problem is a separate question, covered below.

Mid cap funds sit on a flatter index. The top ten of the Nifty Midcap 150 were 16.8% of that index on the same date, so two mid cap funds can diverge far more than two large caps.

How much overlap is too much

There is no official number for investors, and the people who publish numbers disagree. PrimeInvestor says there is no hard cut-off and treats 60 to 65% as high and 70 to 75% as very high. Kuvera calls 40 to 50% high and above 50% very high. Finnovate puts "high" at 30 to 50%. SEBI's only figure is a rule for fund houses: a sectoral or thematic scheme may not overlap more than 50% with another sectoral or thematic scheme, or with any equity category except large cap (measured quarterly as the average of daily values, with existing schemes given until 2029 to comply), and a value fund and a contra fund from the same house may both exist only if their overlap is not more than 50%.

So a pairwise number between 40 and 60% is where most published opinion starts to frown, and above 60% published commentary treats the two funds as substantially the same portfolio. For large cap pairs, expect to be above that line most of the time, for the reason above.

The more useful reading is from the consolidated sheet:

• Top ten stocks above roughly half of your equity shows the funds hold largely the same large positions, whatever their names say.
• One stock above 8 to 10% of the total, through several funds, is a single-company exposure the fund names did not show.
• One sector (financial services is the usual one; it was 37.5% of the Nifty 50 in September 2026) above 35 to 40% of the total is the same reading at sector level.

These are descriptions of what the sheet shows, not thresholds for action.

Does anyone actually hold too many funds?

The data that exists is partial. CAMS's study of investors in smaller (B30) cities, with data to January 2025, found that 47% held one scheme and 11% held more than five. That is 2.08 crore investors in one registrar's smaller-city book, so it says nothing about a 15-fund portfolio built in Bengaluru over eight years. We have not found a national figure from a primary source, so this guide does not quote one.

What we can say is that the overlap problem is an accumulation problem. Nobody buys three large cap funds on one day. They buy one in 2017, another when a colleague recommends it in 2020, and a third because the bank's app suggested it in 2023. The consolidated sheet is how you find out what those three decisions added up to.

The arithmetic of doing something about it

This section describes costs, not recommendations. Whether any of this is right for you depends on your situation, and a decision to sell or switch is advice that only a SEBI registered investment adviser may give.

Switching out of a fund is a redemption and a fresh purchase. For tax it is a sale: on equity funds, gains on units held 12 months or less are taxed at 20%, and gains on units held longer at 12.5% on long-term gains (equity shares and equity funds counted together) above ₹1.25 lakh in a tax year, plus cess. The holding period in the new fund starts from zero. Many diversified equity schemes also charge an exit load, commonly 1% on units redeemed or switched out within a year of each purchase (some charge less, or for shorter periods), and units are redeemed first-in-first-out, so a fund you have been adding to monthly has a trailing twelve months of units still inside the load window.

The alternatives people weigh against that cost: stopping further SIPs into one of the overlapping funds (no tax and no exit load, the existing units stay), directing new money to a fund that holds different things, or spreading any redemption across tax years to stay under the ₹1.25 lakh threshold. Each is a calculation you can do from the consolidated sheet and your CAS. Which one to pick, if any, is the part this site does not answer.

Frequently asked questions

How is mutual fund overlap calculated?
For each stock both funds hold, take the lower of the two portfolio weights and add those up. SEBI put this formula into its February 2026 circular on scheme categorisation. Some tools instead report the share of stock names in common, which is a different and usually larger number.

What percentage of overlap is acceptable between mutual funds?
There is no official figure for investors. Published opinion ranges from 30% to 65% for "high". Between large cap funds, high overlap is structural because all of them must hold 80% in the same 100 companies.

How do I check overlap across more than two funds?
Download each scheme's monthly portfolio spreadsheet from the fund house, multiply each stock's weight by the amount you hold in that scheme, and add up by ISIN across all schemes. The result is your stock-level exposure across the whole portfolio.

Where do I get a fund's holdings?
Every fund house must publish each scheme's full portfolio with ISINs within 10 calendar days of month end, on its own website and on AMFI's, as a spreadsheet. Unitholders with a registered email receive a link each month.

Does switching to reduce overlap cost anything?
A switch is a redemption plus a purchase. It can trigger capital gains tax (20% short-term, 12.5% long-term above ₹1.25 lakh a year on equity funds) and an exit load, commonly 1% within a year of each purchase. Stopping fresh SIPs into a fund triggers no tax and no exit load.

Sources: SEBI circular of 26 February 2026 on categorisation and rationalisation of mutual fund schemes (equity category definitions, overlap formula in Annexure A, 50% overlap limits for sectoral, thematic, value and contra schemes); SEBI Master Circular for Mutual Funds dated 20 March 2026 (clauses 3.8 and 3.9 on categories and the AMFI market-cap list, 3.8.10 on monthly overlap disclosure by AMCs, 6.1 on monthly portfolio disclosure within 10 days in spreadsheet format); AMFI, average market capitalisation of listed companies for the six months ended 30 June 2026; NSE Indices factsheets for Nifty 50, Nifty 100 and Nifty Midcap 150 dated 30 September 2026, and NSE equity index methodology, September 2026; PrimeInvestor, "How to identify mutual fund overlap" (October 2022); Kuvera blog on overlap calculators (August 2026); Finnovate overlap calculator page (June 2026); CAMS and CII, "B30 Locations: Performance & Potential" (data to January 2025); Income-tax Act 2025, sections 196 and 198, in force from 1 April 2026; HSBC Mutual Fund tax reckoner for 2026-27; HDFC Large Cap Fund scheme document, July 2026, on exit load for each purchase or switch-in; Franklin Templeton and HSBC Mutual Fund addenda on first-in-first-out application of exit loads; Kotak Mutual Fund, July 2026, on the tax treatment of a switch. Index constituents and weights are quoted for illustration only and are not recommendatory. Corpus is in the process of registering as an investment adviser with SEBI. Nothing on this page is investment advice. Investment in securities market are subject to market risks. Read all the related documents carefully before investing.