Executive Summary

Index funds carry a persistent cloud of folklore — half-truths repeated in newspaper columns, WhatsApp forwards, and advisor conversations that quietly cost investors real money. This brief deconstructs seven of the most common myths, not to argue that passive investing is always right, but to ensure the reasons investors doubt it are actually grounded in evidence. Most aren't.

The Seven Myths at a Glance

Summary of Seven Myths — Index Funds & the Indian Investor, June 2026

Myths in Detail

Myth 1 — Index Funds Should Protect You in a Correction

When the Nifty 50 dropped roughly 38% during February–March 2020, investors who expected cushioning felt betrayed. But a Nifty 50 index fund is an ownership stake in the 50 largest NSE-listed companies, weighted by free-float market cap. There is no defensive mechanism. When the market falls, the fund falls — by design. The better question is whether active funds did meaningfully better. SEBI scheme disclosure data from 2015–2024 shows the median large-cap active fund underperformed the Nifty 100 TRI in 7 of 10 calendar years, including years with significant corrections. Downside protection comes from your asset mix — equity, debt, gold, international — not from who selects the equities.

Myth 2 — Index Funds Deliver Only 'Average' Returns

William Sharpe's 1991 arithmetic is still correct: before costs, all active investors collectively earn the market return. After costs, they collectively earn less. The TER gap between a direct-plan large-cap active fund (0.7–1.4% p.a.) and a Nifty 50 index fund (0.06–0.20% p.a.) may look small. On a Rs 50 lakh corpus earning 12% gross over 20 years, it produces a Rs 65.77 lakh shortfall — assuming the active fund matches index returns before fees, which SPIVA data suggests is the optimistic case. 'Average' is the wrong word. 'Market return minus minimal costs' is more accurate — and more attractive than most active investors achieve.

Table: 20-year fee drag on Rs 50 Lakh — identical gross returns assumed (illustrative)

Myth 3 — Multiple Index Funds Means Diversification

The Nifty 100 is definitionally the Nifty 50 plus the Nifty Next 50. An investor holding all three funds has doubled their Nifty 50 exposure — the top 50 stocks account for roughly 73–78% of the Nifty 100 by free-float weight. Three fund names in a portfolio tracker is not three sources of diversification. Real diversification means combining instruments with lower correlations: a broad domestic index, a dedicated midcap or smallcap fund, an international index fund, and possibly a factor-based fund. Holding three versions of the same 100 stocks achieves none of that.

Myth 4 — Experienced Investors Should Move to Active

Experience in markets is not the same as edge in markets. A fund manager with 20 years of experience is not necessarily a better stock picker — because the market evolves, incorporates information faster, and features increasingly sophisticated counterparties. The more important number is the behaviour gap: the difference between what the fund earns (time-weighted return) and what the investor actually earns (money-weighted return). Active fund switchers in India show a gap of approximately −4.6% p.a. over ten years. Passive index fund investors with SIPs show a gap close to −0.1% p.a. Experience triggers more switching, not less — which makes the behaviour problem worse, not better.

Table: Behaviour gap by investor archetype — Indian equity funds, 10-year horizon (illustrative)

Myth 5 — Indian Markets Are Too Inefficient for Passive

Partially correct — but applied to the wrong segment. Nifty 50 companies are covered by an average of 38 analysts, with FIIs holding 28–45% of free float. The information environment for HDFC Bank or Infosys is not materially different from their S&P 500 equivalents. In large-caps, the passive case is very strong. Further down the cap spectrum — micro-caps below Rs 500 crore, with 0–2 analysts and minimal institutional ownership — genuine information asymmetry exists. The right response is not to abandon passive investing altogether, but to maintain a passive core in large-caps and allocate selectively to a differentiated small-cap active fund if alpha access in that segment is genuinely the goal.

Myth 6 — Large Portfolios Need Active Management

The fee differential between an active large-cap fund and a Nifty 50 index fund is 0.7–1.0% per year. On a Rs 5 crore corpus earning 12% gross, that gap compounds to Rs 5.75 crore in forgone wealth over 20 years — more than the starting corpus. That assumes the active fund matches index gross returns, which the majority do not. PMS and AIF structures charge more, not less, and generate higher capital gains events through active turnover. Scale does not make active management cheaper or more effective. It makes the fee drag larger.

Table: 20-year fee drag on Rs 5 Crore corpus — 0.85% annual fee differential, 12% gross return (illustrative)

Myth 7 — 'Someone Is Watching' Means My Money Is Safe

A fund manager can protect you from one specific thing: concentration in a company that fails while the market recovers. That's stock selection oversight — it's real and has value. What no manager can reliably do is call a broad market correction in advance, move to cash, and shield the portfolio from systemic decline. SEBI equity fund mandates don't permit sustained high cash positions anyway. In a correction, an actively managed large-cap fund and a Nifty 50 index fund fall for the same reason: both hold equities. The additional cost of the 'someone watching' belief is behavioural — it creates expectations of intervention that, when unmet, trigger the switching and the performance-chasing that Table 4 shows is so destructive.

Conclusions

• Myth 1:  Index funds fall in corrections because they hold equities — not by design failure. Asset allocation determines downside protection, not fund selection method.

• Myth 2:  'Average returns' understates what passive investing delivers after costs. Net of fees, the passive investor outperforms the majority of active investors in every major Indian equity category over 10 years.

• Myth 3:  Nifty 50 + Nifty 100 + Nifty Next 50 is not diversification. It's concentration with extra steps. True diversification requires lower-correlation instruments across cap bands, geographies, and asset classes.

• Myth 4:  Experience doesn't reduce the behaviour gap — it often amplifies it. Passive investors exhibit a gap near zero. Active fund switchers lose ~4.6% per year to their own reactions.

• Myth 5:  Indian market inefficiency is real but segment-specific. The passive case is strongest exactly where most investor money sits: large-cap equities covered by dozens of analysts.

• Myth 6:  Fee drag on large portfolios is not a small number. A 0.85% annual difference on Rs 5 crore costs Rs 5.75 crore over 20 years — more than the original corpus.

• Myth 7:  Active managers provide stock selection oversight. They do not provide market risk protection. Both fund types fall in a correction.

Disclaimer

This content is for educational and informational purposes only and does not constitute investment advice or a recommendation of any specific fund or security. All return projections and corpus growth figures are hypothetical illustrations designed to demonstrate mathematical principles — actual market returns vary significantly. SPIVA India 2025 data covers the period ending December 2024. Expense ratio figures are approximate averages from AMFI and SEBI disclosures as of Q1 2026. All corpus growth calculations assume identical gross returns across scenarios unless stated otherwise. Readers are encouraged to consult a SEBI-registered investment advisor before making investment decisions.