The diversification that isn’t
Many investors add a second, third, or fourth mutual fund because it feels safer - more funds, more spread, less risk sitting in any one place. But diversification isn’t measured by how many funds you own. It’s measured by how different what’s inside them actually is. Hold three large-cap funds from three different fund houses, and there’s a good chance you’re looking at the same 15–20 stocks wearing different labels.
This is called portfolio overlap, and it’s one of the quieter ways a portfolio can look diversified on paper while behaving like a much smaller, more concentrated bet in practice.
What overlap actually means
Overlap is the degree to which two or more funds in your portfolio hold the same underlying stocks. If Fund X and Fund Y both hold a large position in the same company, that stock is influencing your returns twice over - once through each fund - even though you think of them as two separate investments.
A quick way to see it
Take two funds you already hold. List each one’s top 10–15 holdings, and check how many names repeat across both. As a rough guide: some overlap is completely normal - a 20–30% overlap between two large-cap funds is common, since most large-cap managers draw from a similar pool of liquid, well-researched companies. Overlap above 50–60% starts to matter more, because at that point the two funds are largely tracking each other rather than genuinely diversifying you.
Seeing it in your actual exposure
Here’s where it gets concrete. Say you’ve invested ₹3 lakh in Fund X and ₹4 lakh in Fund Y, and both funds hold the same stock - at 8% of Fund X’s portfolio and 6% of Fund Y’s.
- Your exposure to that stock through Fund X: 8% of ₹3,00,000 = ₹24,000
- Your exposure through Fund Y: 6% of ₹4,00,000 = ₹24,000
- Total exposure to a single stock: ₹48,000 - out of ₹7,00,000 invested, or roughly 6.9%
That’s a meaningfully larger bet on one company than either fund’s fact sheet alone would suggest - and it happened without you ever deciding to concentrate your portfolio that way.
When overlap is a problem, and when it isn’t
Overlap on its own isn’t automatically bad. Many well-run large-cap funds are benchmarked against similar indices and invest in India’s most liquid, widely-researched companies - some convergence is expected, not a red flag.
It becomes worth addressing when the overlap is high enough that you’re effectively paying two, three, or four sets of expense ratios to hold what is largely one portfolio. At that point, you’re not spreading risk - you’re paying more to own the same risk, spread across more paperwork.
The goal was never zero overlap. It’s making sure the overlap you do have is a choice, not something that built up quietly while you were adding funds one at a time.