From SohajPedia, the daily world briefing
Sensex
When Indian television says 'the market rose today', it usually means one number: the Sensex. It is the benchmark index of the Bombay Stock Exchange — a single figure that tracks 30 of India's largest and most actively traded companies, and acts as a shorthand for the health of the whole market.
The Sensex in numbers
From base to today (index level)
An index level is not a price — it tracks how the basket's total market value has grown since the base period.
What the Sensex measures
The Sensex — short for Sensitive Index — was first compiled in 1986, with a base period of 1978–79 set at 100. Its 30 companies are chosen to represent the major sectors of the Indian economy: banking, information technology, energy, automobiles, pharmaceuticals and others. When most of those heavyweight shares rise, the Sensex rises; when they fall, it falls. Because the list is reviewed and changed over time, the Sensex always reflects what big-company India looks like now, not what it looked like decades ago.
How the number is calculated
The Sensex is weighted by free-float market capitalisation. In plain words: a company's influence on the index depends on the total market value of the shares actually available for public trading — not shares locked up with promoters or the government. A giant like Reliance Industries therefore moves the index far more than the smallest member does. The level itself is a ratio against that 1978–79 base of 100, which is why an index that began at 100 now stands in the tens of thousands.
Why it moves
Company earnings, interest-rate decisions by the Reserve Bank of India, government budgets, oil prices and global markets all push the Sensex around — but the biggest single force in recent years has been fund flows. Foreign institutional investors buying or selling Indian shares in size can swing the index hundreds of points in a day. In November 2026, record foreign buying of about ₹53,170 crore helped drive the Sensex to 81,879.40 — a run covered in SohajPedia's daily market briefing.
Sensex or Nifty?
The Sensex's younger rival is the Nifty 50, the benchmark of the National Stock Exchange, which tracks 50 companies instead of 30. The two usually move together — they are measuring much the same economy — and professional investors tend to watch the Nifty more closely because its derivatives market is deeper. For everyone else, the Sensex remains the number India grew up with: older, narrower, and still the headline.
Frequently asked questions
See also
References
Photograph: the BSE building at Dalal Street, via Wikimedia Commons.