Sensex is the older of India's two big benchmark indices and probably the one your parents grew up hearing about on Doordarshan. While the Nifty 50 has become more popular among traders in the last 15 years, Sensex remains the symbolic face of Indian stock markets. Here's everything you need to know — what it is, the 30 companies inside, how it's calculated, and how you can invest in it.
What does Sensex actually stand for?
Sensex is short for "Sensitivity Index." It's the flagship index of the Bombay Stock Exchange (BSE) — the oldest stock exchange in Asia, founded in 1875. The Sensex itself was launched in 1986 with a base year of 1978–79 and a base value of 100. As of 2026, Sensex trades around 76,000 — meaning India's top 30 companies have grown about 760× over four decades, before counting dividends.
When Indian news anchors say "the market hit a new high today," they're often referring to Sensex breaching a round number. Crossing 50,000 in 2021 was a major headline. Crossing 75,000 in 2024 was another. These round-number milestones are media-driven but they do reflect real, sustained growth in India's economy.
How many companies are in Sensex?
Sensex tracks 30 of the largest and most actively traded stocks on the BSE, representing major sectors of the Indian economy. The current constituents include Reliance Industries, TCS, HDFC Bank, Infosys, ICICI Bank, Bharti Airtel, State Bank of India, ITC, Hindustan Unilever, Larsen & Toubro, Kotak Mahindra Bank, Axis Bank, Maruti Suzuki, Asian Paints, Bajaj Finance, Mahindra & Mahindra, Sun Pharma, Tata Steel, Tata Motors, Power Grid, NTPC, Nestle India, Bajaj Finserv, Titan, UltraTech Cement, IndusInd Bank, Tech Mahindra, Wipro, JSW Steel, and Adani Ports.
Most of these names overlap with the Nifty 50 — Sensex is essentially a smaller subset of similar blue chip stocks.
How Sensex is calculated
Like Nifty 50, Sensex uses the free-float market capitalization weighted method. The calculation factors in only the shares freely available for trading (excluding promoter holdings) and weights larger companies more heavily. Reliance Industries alone holds about 10% weight in Sensex — so a 2% move in Reliance moves Sensex 0.2% all by itself.
The base value of 100 in 1978-79 means the current Sensex value of 76,000 represents a 760× total return over 47 years. That works out to about 16% compound annual growth, including dividends. Pretty extraordinary by any global standard.
Sensex vs Nifty 50 — which to follow?
Honest answer — it barely matters. Both indices move within 0.1–0.2% of each other most days. The main differences:
| Factor | Sensex | Nifty 50 |
|---|---|---|
| Exchange | BSE | NSE |
| Number of stocks | 30 | 50 |
| Launched | 1986 | 1996 |
| Base year | 1978–79 | 1995 |
| Base value | 100 | 1,000 |
| Current level (2026) | ~76,000 | ~23,000 |
| Trading volume in derivatives | Lower | Higher |
Nifty 50 has more F&O liquidity, which is why traders prefer it. For long-term investing, both work equally well — pick either Sensex Index Fund or Nifty 50 Index Fund based on whichever has slightly lower expense ratio at the time you're investing.
Sensex history — the milestones
A walk through the major round numbers tells you the story of modern India:
- 1990: Crossed 1,000 for the first time (took 5 years from launch)
- 2006: Crossed 10,000 (boom of the early 2000s)
- 2008: Hit 21,000 in January, crashed to 8,500 by November (global financial crisis)
- 2014: Crossed 25,000 (post-election rally)
- 2017: Crossed 30,000 (steady economic growth)
- 2020: Crashed to 25,000 in March (COVID), recovered to 47,000 by year-end
- 2021: Crossed 50,000 — major media moment
- 2024: Crossed 75,000 — fresh all-time highs
- 2026: Trading around 76,000
Every crash has been followed by a recovery to new highs within a few years. That's the long-term lesson — patience pays.
How to invest in Sensex
Same approach as Nifty 50. You can invest through Sensex Index Funds or BSE Sensex ETFs:
- HDFC Sensex Index Fund — expense ratio ~0.20%, SIP from ₹500
- ICICI Prudential BSE Sensex Index Fund — similar costs
- SBI BSE Sensex ETF — lowest expense ratio (~0.07%) but needs a demat
The same SIP discipline applies — start small, invest monthly, hold for 10+ years. See my compounding guide for what that does over time.
What moves Sensex
The same things that move any large-cap index — earnings of constituent companies (especially the top 5), RBI policy decisions, government policy moves (Budget, regulatory changes), global cues (US markets, oil prices, dollar index), foreign institutional investor (FII) flows, and quarterly results season. During results season (Jan, Apr, Jul, Oct) Reliance's results alone can move Sensex by 0.5% or more.
Track Sensex live on the home page alongside other major indices. Sensex data, like all market data on this site, comes from Google Finance with about a 20-minute delay — fine for understanding the market direction, not for active trading.