Index Funds in India: When “Passive” Investing Isn’t So Simple Anymore

CV or resume — same thing, right?

Most people use the terms interchangeably. But when it actually matters — say, during a job application — the difference suddenly becomes important. The structure, intent, and outcomes are not the same.

Something similar is happening in the world of index funds today.

We casually say, “Just invest in an index fund,” as if it’s one obvious, straightforward choice. In reality, index investing in India has evolved into a growing list of similar-sounding options — enough to confuse not just investors, but even mutual fund distributors.

Large-cap index fund? Sure.
But which large-cap index?

A decade ago, index investing was refreshingly simple. Most investors had just two familiar choices:

• Nifty 50
• BSE Sensex

That simplicity no longer exists.

Today, even within the large-cap universe alone, investors encounter names such as:

• Nifty 50 Index
• Nifty Next 50 Index
• Nifty 50 Equal Weight Index
• Nifty 100 Index
• Nifty 100 Equal Weight Index
• Nifty 100 Low Volatility 30 Index
• Nifty 100 Quality 30 Index
• Nifty Top 10 Equal Weight Index
• BSE Sensex Index

And these are only indices, not mutual fund schemes.

Once multiple AMCs launch funds tracking each of these indices, the number of choices multiplies quickly.

Choice is good. Too much choice without context is not.

Most investors assume that all large-cap indices behave similarly. They don’t.

The difference lies not in the label “large cap,” but in how the index is constructed.

Let’s simplify this.

1️⃣ Traditional Market-Cap Weighted Indices

Examples

• Nifty 50
• BSE Sensex
• Nifty 100

How they work
Stocks are weighted based on market capitalization. The larger the company, the greater its influence on index returns.

What this means for investors

• High concentration in the top 5–10 companies
• Returns closely mirror headline market movements
• Lower churn and long history of data

These indices form the core building blocks of most passive portfolios.

2️⃣ Equal Weight Large-Cap Indices

Examples

• Nifty 50 Equal Weight
• Nifty 100 Equal Weight
• Nifty Top 10 Equal Weight

How they work
Every stock carries the same weight, regardless of size.

What changes

• Reduced concentration risk
• Higher exposure to relatively smaller large-cap stocks
• Higher volatility and more frequent rebalancing

These indices often perform well during broad-based market rallies, but may lag when returns are driven by a handful of mega-caps.

Same companies. Very different behaviour.

3️⃣ Factor-Based Large-Cap Indices

Examples

• Nifty 100 Low Volatility 30
• Nifty 100 Quality 30

How they work
Stocks are selected using predefined, rule-based factors such as:

• Price stability
• Profitability
• Balance-sheet strength

What investors should know

• These are not defensive guarantees, despite how they sound
• Performance varies across market cycles
• Periods of underperformance are normal and unavoidable

These indices introduce strategy into index investing.

And This Is Still Only Large Caps

If this already feels overwhelming, it’s worth noting that we haven’t moved beyond large caps yet.

Once we step into broader market indices, the complexity increases further.

Examples

• NIFTY Large Midcap 250 Index
• Nifty 200 Momentum 30
• Nifty 200 Quality 30
• Nifty Alpha Low Volatility 30
• BSE Low Volatility Index

These indices:

• Combine large and mid-cap stocks
• Use momentum, quality, or volatility screens
• Can behave very differently from plain vanilla index funds

At this point, index investing starts to resemble strategic allocation, not just passive exposure.

Beyond this lie:

• Mid-cap and Small-cap indices
• Factor variants within each category
• Sectoral indices like IT, Banking, Pharma, Realty, PSU

These indices are:

• More volatile
• More cyclical
• Heavily dependent on patience and discipline

Here, index investing is clearly not “set and forget.”

While index funds are passive in portfolio construction, selecting an index is an active decision.

Different indices imply:

• Different volatility
• Different drawdowns
• Different recovery paths
• Different long-term experiences

Passive fund.
Active choice.

Just as a CV and a resume serve different purposes despite sounding similar, index funds demand understanding beyond their names.

Instead of chasing variety, investors may benefit from a simpler framework:

• Use broad, market-cap weighted indices as the portfolio core
• Add factor or thematic indices sparingly and consciously
• Avoid overlapping indices that unknowingly duplicate exposure
• Fewer well-understood indices held patiently often work better

Index funds were meant to simplify investing — not replace one form of complexity with another.

Index funds remain powerful tools for long-term wealth creation.

But in a world filled with similar-sounding indices and abundant choice, simplicity now requires understanding.

The goal isn’t to own every index.
It’s to own the right ones, for the right reasons, for long enough.

If you’re unsure whether your index fund choices are truly diversifying your portfolio — or quietly duplicating risk — it may help to step back and view the portfolio as a whole.