What Is the SENSEX? The BSE's 30-Stock Benchmark Explained
The S&P BSE SENSEX — short for "Sensitive Index" — is the benchmark index of the Bombay Stock Exchange (BSE), India's oldest exchange. It tracks 30 of the largest, most established, and financially sound companies listed on the BSE.
How it's calculated
Like the NIFTY, the SENSEX is free-float market-capitalisation weighted: each company's influence on the index is proportional to the market value of its freely tradable shares. A move in a heavyweight constituent shifts the index far more than a move in a smaller one.
Why 30 stocks still represent the market
Although it holds only 30 companies, those 30 are among the largest in India and span the major sectors, so the SENSEX captures a large share of total market value. That's why it works as a shorthand for "how the Indian market did today."
SENSEX vs NIFTY 50
The NIFTY 50 is the NSE's 50-stock equivalent. The indices overlap heavily in their largest holdings and tend to move together; the main differences are the exchange, the number of constituents (30 vs 50), and the index provider's selection rules. Browse index levels on the indices pages.