Sensex
The BSE's benchmark index of 30 large Indian companies, weighted by free-float market capitalisation.
Formula
Index Value = (Current Free-Float Market Capitalisation of Constituents / Base Market Capitalisation) x Base Value
Unit
index points
In depth
India's oldest and most widely quoted index, the Sensex has a base of 100 as of 1978-79, which is why its level is numerically much higher than the Nifty's despite tracking a similar market. With only 30 constituents it is more concentrated than the Nifty 50, so single-stock moves affect it more. The two indices correlate very closely, and the choice between them for a passive investor is largely a matter of which has the cheaper fund available. Historical Sensex charts are usually price indices excluding dividends, which understates what a holder would actually have earned.
Worked example
The Sensex and Nifty typically move within a few basis points of each other on any given day. The large numerical difference between their levels reflects different base years and base values, not different performance.
Illustrative figures, chosen so the arithmetic is easy to follow. Not a live price and not a valuation of any company.
Educational reference only
This entry explains what “Sensex” means. It is not investment advice and not a recommendation to buy or sell any security. Any numbers above are illustrative, not live prices, and nothing here predicts price direction or rates a stock. Consider your own circumstances and consult a SEBI-registered investment adviser before acting.