Highlights

  • Understand SEBI’s 2% annual tracking error threshold to identify the best-performing ETF that truly replicates its index.
  • Compare expense ratios across ETFs tracking the same benchmark—lower costs directly boost your returns over time.
  • Evaluate liquidity through bid-ask spreads and trading volumes to ensure you can enter or exit positions efficiently.
  • Learn post-Budget 2024 tax rates—20% STCG and 12.5% LTCG—to calculate realistic after-tax returns on ETF investments.

Introduction

ETFs may look boring at first glance, but the wrong one can quietly cost you more than a bad stock pick.

India’s ETF market held more than ₹10 lakh crore in assets as of Feb 2026. As more investors seek the best ETF to buy, making an informed choice matters. Unlike picking stocks, selecting ETFs requires evaluating specific performance metrics that separate truly efficient funds from mediocre trackers. Here’s what you need to check before investing.

Tracking Error: How Closely Does it Follow the Index?

Tracking error measures the difference between an ETF’s returns and its benchmark index. SEBI mandates that tracking error should not exceed 2% annually under normal circumstances.

Lower tracking error means better replication. If a NIFTY 50 ETF shows 0.3% tracking error while another shows 1.8%, the first delivers returns closer to the actual index.

Tracking error arises from fund expenses, cash balances maintained for liquidity, and delays during index reconstitution. Check 1-year, 3-year, and 5-year tracking errors on AMC websites—consistency matters more than a single period’s performance.

Expense Ratio: Keep Costs Low

ETF expense ratios cover the fund management and operational costs of running the scheme. SEBI requires asset management companies to disclose the Total Expense Ratio (TER) for every ETF.

When comparing ETFs that track the same index, it is advisable to choose the one with a lower expense ratio, as this can help improve your overall net returns over time

Liquidity: Can You Trade Easily?

Liquidity determines how smoothly you can buy or sell ETF units without impacting prices. NSE defines bid-ask spread as the transaction cost for small trades, while impact cost measures the price markup when executing your desired quantity.

Check:

  • Bid-ask spread: Narrower spreads (below 0.1%) indicate better liquidity
  • Daily trading volume: Higher volumes reduce execution risk
  • AUM size: Larger funds generally trade more actively

For the best performing ETF experience, prioritise funds with consistent daily volumes above ₹5 crore and tight spreads. Illiquid ETFs can force you to accept unfavourable prices during exits.

Tax Implications: Know Your Post-Tax Returns


After Budget 2026, ETF taxation depends on the underlying asset class, and this directly affects your actual returns:

Holding PeriodTax RateExemption
≤12 months20% STCGNone
>12 months12.5% LTCGFirst ₹1.25 lakh/year

Gold ETFs and other categories follow different tax rules based on asset classification. Always verify specific ETF taxation before calculating expected returns. Post-tax returns determine your actual wealth creation.

Finding Your Best Fit


Choosing the best ETF to buy means balancing these metrics together—not chasing yesterday’s top performer. Start with low tracking error (under 1%), confirm adequate liquidity, and factor in tax implications for your holding period. The right ETF works quietly in your portfolio, delivering index returns efficiently without surprises.

FAQs

1. What is a good tracking error for an ETF in India?

SEBI mandates that tracking error should not exceed 2% annually under normal circumstances. Lower tracking error indicates better index replication. Check 3-year and 5-year data for consistency.

2. What is the tax on ETF gains after Budget 2026?

After Budget 2026, the taxation of ETFs depends on the type of underlying asset:

Equity ETFs (with domestic equity exposure) held for more than 12 months attract 12.5% LTCG tax on gains above ₹1.25 lakh. Gains within 12 months are treated as short-term and taxed at 20%

3. How do I check if an ETF is liquid enough?

Check NSE bid-ask spread (narrower is better), daily trading volume, and AUM size. Impact cost measures liquidity more accurately than volume alone. Spreads below 0.1% indicate good liquidity.

4. Where can I find official ETF tracking error data?

AMCs disclose tracking error and tracking difference on their websites and the AMFI website monthly for 1-, 3-, and 5-year periods, as per SEBI requirements. Check consistently before investing.