Portfolio overlap is the degree to which two or more mutual funds in your portfolio hold the same stocks — high overlap means less actual diversification than the number of funds suggests.
Portfolio overlap is measured as the percentage of common stocks between two funds, weighted by either stock count or portfolio allocation. For example, if Fund A and Fund B each hold 50 stocks and 30 of those stocks are the same, the overlap is 60%. High portfolio overlap between funds defeats the purpose of holding multiple funds — if they both fall and rise together (because they hold the same stocks), you don't have true diversification; you just have higher management costs.
Many investors own 10–15 mutual funds thinking they're diversified. But if those funds all hold Reliance, HDFC Bank, and Infosys as their top positions, they move together. It's like owning 10 plates of dal but calling it a diverse meal. Portfolio overlap analysis reveals when two funds are essentially doing the same thing — at which point, owning both just increases costs without adding diversification benefit.
Compare the top 20–30 holdings of each fund from their factsheets.
Count (or compute % weight of) stocks that appear in both portfolios.
If overlap is >60% between two equity funds: consider consolidating to one.
Tools: Coin by Zerodha, Value Research, FundsIndia offer overlap analysis.
Acceptable overlap: 20–30% between two different category funds is natural.
You already hold Mirae Asset Large Cap Fund. Before adding HDFC Top 100, check overlap: - Mirae Asset Large Cap: top holdings include HDFC Bank, Infosys, ICICI Bank, Reliance, L&T. - HDFC Top 100: top holdings include HDFC Bank, ICICI Bank, Infosys, Reliance, Bharti Airtel. Overlap: 4 of 5 top positions are identical. Adding HDFC Top 100 gives you almost no new diversification — just higher cost.