Understanding Mutual Fund Portfolio Overlap and How to Analyze It
Many investors believe that owning more mutual funds automatically makes their portfolio safer. However, if those funds hold the same underlying stocks, you might have a high portfolio overlap. Here is how overlap works and how to analyze it.
When assembling a mutual fund portfolio, diversification is the primary goal. By spreading money across multiple funds, you aim to limit risk. But if you own two or three funds in the same category (for example, three active Flexi Cap funds), you might just be buying the same set of blue-chip stocks multiple times.
This duplication is called **mutual fund portfolio overlap**. It creates a false sense of security while compounding your management fees.
How Portfolio Overlap is Calculated
Portfolio overlap is not just about the number of shared stocks. It is calculated based on the **minimum common weight** of each shared stock in both portfolios.
For example, let's say you want to calculate the overlap between Fund A and Fund B for a single stock, Reliance Industries:
- If Fund A holds Reliance at **8%** weight.
- If Fund B holds Reliance at **5%** weight.
- The common overlap for Reliance is the minimum of the two, which is **5%**.
To find the total overlap between two funds, you sum this minimum common weight for every single shared stock in their portfolios. If the sum is 65%, it means 65% of your money in these two funds is invested in the exact same assets in the exact same proportion.
Interpreting Overlap Percentages: What is Healthy?
When comparing two equity funds, use the following thresholds to evaluate their overlap:
| Overlap Range | Significance | Action Recommended |
|---|---|---|
| < 30% | Low Overlap | Good diversification. Safe to hold both. |
| 30% - 50% | Moderate Overlap | Acceptable if funds have different strategies. |
| > 50% | High Overlap | Excessive duplication. Consider consolidating. |
The Risks of High Portfolio Overlap
Owning two highly overlapping funds exposes you to several structural disadvantages:
- Clones of the Index: If two active funds overlap by 70%, they will perform almost identically, closely mimicking a low-cost index fund. However, you are paying active management fees (often 1.5% to 2% p.a. for regular plans) for both.
- Concentration Risk: If a specific stock or sector faces a downturn, both of your funds will fall simultaneously, failing to provide the safety net of diversification.
- Complex Portfolio Management: Tracking 8-10 funds with high overlap is mentally taxin, makes tax filing harder, and adds zero performance value compared to a clean 3-4 fund portfolio.
How to Reduce Portfolio Overlap
To optimize your mutual fund portfolio and clean up overlap, follow these steps:
- Avoid Category Duplication:Try not to own more than one active fund in the same SEBI category. For example, don't hold two Large Cap funds or two active Small Cap funds.
- Mix Strategies: Pair active funds with passive index funds, or pair growth-oriented funds with value-oriented funds. Value funds and growth funds typically hold very different stocks, naturally keeping overlap low.
- Check the Overlap Tool: Before buying a new fund, run it through the WhoHolds overlap tool against your existing funds. If the overlap is above 40%, look for a different fund or category.
Frequently Asked Questions
- Is some overlap normal?
- Yes. In the Indian market, large-cap funds have a limited universe of ~100 stocks to choose from. Therefore, two large-cap funds will almost always have an overlap of 40% to 60%. This is normal, but it highlights why you rarely need to own more than one large-cap fund.
- How many mutual funds should an investor own?
- For most retail portfolios, 3 to 5 funds are more than enough to achieve complete diversification across large-cap, mid-cap, small-cap, and international equities.
- Does sector overlap matter?
- Yes. Even if two funds don't share the exact same stocks, if they both allocate 30% of their capital to the financial sector, your portfolio is heavily dependent on bank performances.