What is Correlation Risk?
Correlation Risk is the risk of holding multiple investments that behave identically during a market downturn. Correlation is measured on a scale from −1 (moves perfectly opposite) to +1 (moves perfectly together). Two small cap funds with correlation of +0.92 will essentially rise and fall in tandem — owning both provides almost no diversification benefit.
Most Indian investors believe they are diversified because they own 4–5 mutual funds. In reality, if those funds are highly correlated, a market crash will hit all of them simultaneously and with similar magnitude. This is the trap correlation risk creates.
Why Small Cap Funds Are Especially Prone to High Correlation
The Nifty Smallcap 250 index contains 250 stocks. Most active small cap funds hold 60–100 stocks. The most popular names — Tube Investments, Dixon Technologies, Karur Vysya Bank, Brigade Enterprises — appear in the top holdings of five, six, or even eight different small cap funds. When these stocks correct, all those funds correct together.
The "Five Fund Trap" — Indian Small Cap Portfolio
An investor holds Nippon India Small Cap, HDFC Small Cap, Kotak Small Cap, SBI Small Cap, and DSP Small Cap. They feel diversified. But the correlation between most of these funds over a rolling 3-year period is typically above 0.88–0.92. In the September 2024 small cap correction, all five funds fell between 18–26% simultaneously — providing exactly zero protection from each other. The investor had five times the anxiety of a single fund with no additional protection.
| Fund Pair | Estimated Correlation | Diversification Benefit |
|---|---|---|
| Nippon + HDFC Small Cap | ~0.91 | Very Low |
| SBI + Canara Robeco Small Cap | ~0.84 | Some |
| Small Cap + Mid Cap Fund | ~0.78 | Moderate |
| Small Cap + International Fund | ~0.45 | Good |
| Small Cap + Debt Fund | ~0.10 | Excellent |
How to Build a Low-Correlation Portfolio
True diversification means holding assets that do not fall together. If you want small cap exposure, one good small cap fund is enough. Combine it with a different asset class — a mid or large cap fund, an international fund, or debt — to achieve meaningful correlation reduction. Adding a second or third small cap fund adds concentration risk, not diversification.