What is Portfolio Overlap in Mutual Funds?
What is Portfolio Overlap in Mutual Funds? The Hidden Pitfall in Your Mutual Fund Portfolio Investing in multiple mutual funds is a strategy most Indian investors adopt believing it guarantees diversification. You pick a large-cap fund, a mid-cap fund, a flexi-cap fund, and maybe a multi-cap fund — feeling confident that your money is spread across hundreds of stocks. But what if all four funds hold the same 30 stocks? What if Reliance Industries, HDFC Bank, Infosys, and TCS appear in every single one of your funds? This phenomenon — where two or more mutual funds in your portfolio hold the same underlying stocks — is called Portfolio Overlap. It is one of the most under-discussed yet significant risks in personal finance in India. Despite the SEBI (Securities and Exchange Board of India) pushing for greater transparency in fund disclosures since 2021, a large majority of retail investors in 2026 are still unaware of how heavily their portfolios overlap. In this comprehensive guide, we will explore everything you need to know about portfolio overlap in mutual funds — what it is, why it happens, how to measure it, its impact on your wealth, and most importantly, how to fix it. Whether you are a first-time SIP investor or a seasoned market participant, this blog will help you take a sharper, more informed look at your mutual fund holdings. 💡 Key Takeaway More mutual funds does NOT automatically mean more diversification. Portfolio overlap can cause you to unknowingly concentrate your investments in the same stocks, defeating the very purpose of investing in multiple funds. What is Portfolio Overlap in Mutual Funds? Portfolio overlap in mutual funds refers to the degree to which two or more mutual funds in an investor’s portfolio hold the same stocks or securities. When you invest in multiple funds, each fund has its own portfolio of stocks. If Fund A holds Reliance Industries and Fund B also holds Reliance Industries, then there is an overlap on that stock. Overlap is typically expressed as a percentage. A 40% portfolio overlap between two funds means that 40% of the stocks (by weight) are common between them. The higher the overlap percentage, the more similar the two funds are — and the less genuine diversification you are getting. A Simple Definition Portfolio Overlap = The percentage of stocks (by number or weight) that are common between two or more mutual fund portfolios. An Indian Example — 2026 Context Let’s say you invest in two popular large-cap funds: Fund A (Nifty 50 Index Fund) holds 50 stocks — Reliance, HDFC Bank, Infosys, TCS, ICICI Bank, etc. Fund B (Large Cap Actively Managed Fund) holds 30 stocks — of which 22 are also present in Fund A. In this case, the overlap is extremely high. You effectively hold the same stocks in two different fund wrappers, paying two sets of expense ratios (Total Expense Ratio or TER as mandated by SEBI) without gaining additional diversification. Why Does Portfolio Overlap Happen? 1. Concentration of Indian Markets The Indian stock market, despite having over 5,000 listed companies on BSE, is heavily concentrated at the top. The Nifty 50 index — which represents India’s 50 largest companies by free-float market capitalisation — accounts for approximately 60-65% of the total market capitalisation as of 2026. This means any large-cap or diversified fund will almost inevitably hold these top stocks. 2. Benchmark Hugging by Fund Managers Many active fund managers in India stay close to their benchmark index to manage tracking error risk. A flexi-cap, multi-cap, or large & mid-cap fund will often replicate a significant portion of the Nifty 100 or BSE 200, leading to heavy overlap with pure large-cap index funds. 3. Popularity of Certain Stocks Stocks like HDFC Bank, Reliance Industries, Infosys, TCS, ICICI Bank, Bajaj Finance, and Axis Bank appear across virtually every category of fund — from large-cap to balanced advantage funds. These seven to ten mega-cap stocks form the core holding of almost all diversified Indian mutual funds, creating a structural overlap. 4. Category Similarities SEBI’s October 2017 circular on mutual fund categorisation created defined categories. However, categories like Large Cap, Flexi Cap, Multi Cap, and Large & Mid Cap often end up holding very similar stocks, especially in the large-cap segment (the top 100 stocks by market cap as defined by AMFI every 6 months). 5. Investor Behaviour — Buying Multiple Funds in Same Category A very common mistake Indian investors make is buying 3-4 funds within the same category. For example, investing in SBI Large Cap Fund, ICICI Prudential Bluechip Fund, and Axis Bluechip Fund simultaneously creates massive overlap since all three funds are large-cap funds investing in the same universe of top 100 stocks. How to Calculate Portfolio Overlap — Step-by-Step Calculating portfolio overlap manually can be tedious, but understanding the process gives you clarity on what you own. Here is a simple methodology: Manual Method Download the latest factsheets of both mutual funds from the AMC (Asset Management Company) website or AMFI (Association of Mutual Funds in India) portal. List the top 10-20 holdings of each fund along with their portfolio weight (%). Identify common stocks between the two funds. Add up the weights of the common stocks from each fund. Overlap % = (Sum of weights of common stocks in Fund A + Sum of weights in Fund B) / 2 Quick Numerical Example Stock Fund A Weight (%) Fund B Weight (%) Common? HDFC Bank 9.5% 8.2% Yes ✅ Reliance Industries 8.8% 7.6% Yes ✅ Infosys 7.2% 6.5% Yes ✅ TCS 6.5% 5.8% Yes ✅ ICICI Bank 5.9% 5.1% Yes ✅ Sun Pharma 3.2% — No ❌ Zomato — 3.8% No ❌ Total Common Weight 37.9% 33.2% Avg Overlap: ~35.5% In the above example, the two funds have approximately 35.5% overlap — meaning more than one-third of your investment is duplicated across both funds. Using Online Tools (Recommended for Indian Investors in 2026) Several Indian fintech platforms now offer portfolio overlap calculators that automate
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