Sensex Tracks 30 Companies, Nifty 50 Tracks 50; BSE Reshuffle Takes Effect June 2026

The Sensex and the Nifty 50 are two share indexes of the Indian market. Each is a basket of large listed companies, and each follows its own rules on which companies enter, how much weight they carry and when the list changes.

The Sensex is calculated for the Bombay Stock Exchange (BSE), and the Nifty 50 is an index of the National Stock Exchange of India (NSE). Both use the same core weighting method, but they differ in size and base year. The sections below set out those rules and the BSE reshuffle set to take effect in June 2026.

Free-Float Value Sets Each Company's Weight

Both indexes weight companies by free-float market capitalisation. A company's market capitalisation is its share price multiplied by the number of shares it has issued, and that count includes shares added through corporate actions and scrip replacements.

Free-float capitalisation takes that total and removes the part held by directors. Only the shares readily available for trading count toward a company's weight in the index. A company whose directors hold a large block therefore carries less weight than its total market value would suggest.

The Nifty 50 was first weighted by full market capitalisation and moved to the free-float method on 26 June 2009. Under that method, a stock's movement counts in the index in proportion to the value of its tradable shares, so a change in the price of a heavily held company moves the index less than the same change in a widely held one.

The Sensex Tracks 30 Companies Against a 1979 Base

The Sensex has 30 constituents. They are well-established and financially sound companies, among the largest and most actively traded on the Bombay Stock Exchange, and representative of various industrial sectors of the Indian economy.

The base year is 1978-79. The base value is 100, set on 1 April 1979. The index level is the current free-float value of the 30 companies measured against that base. A Sensex figure therefore shows how far the group's free-float value has moved from the 1979 starting point, not the price of any single share.

The BSE also publishes related indexes, including the Sensex 50 and the Sensex Next 50. These are covered by the same periodic reconstitution as the BSE 100, which is described later in this explainer.

The Nifty 50 Tracks 50 Companies Across 13 Sectors

The NIFTY 50 tracks 50 large companies listed on the NSE, spanning 13 sectors. Its base date is 3 November 1995, the day NSE's equity segment completed one year of operations. The base value is 1,000, with a base capital of ₹2.06 trillion. The index was launched on 22 April 1996.

The Nifty's base value of 1,000 is ten times the Sensex's base value of 100. The two index levels therefore sit on different scales and cannot be compared point for point, even though both are free-float weighted.

The 50 companies do not carry equal weight. Because weights follow free-float value, the largest tradable companies in the index move its level more than smaller members do. A reader looking at a single day's Nifty move is seeing the combined effect of those weights, not a simple average of the 50 stocks.

Eligibility Tests and the Nifty's Semi-Annual Review

To enter the Nifty 50, a company must have an average impact cost of 0.50% or less over the previous six months. That test is measured for 90% of observations on a ₹100 million basket.

A company should have a minimum listing history of one month as of the cut-off date.

The index is rebalanced semi-annually. The cut-off dates are 31 January and 31 July each year, and each review uses average data from the six months before the cut-off date. Changes are announced with four weeks' notice.

Because changes follow the two cut-off dates, a stock's place in the index is not decided by a single day's price move. The review looks at six months of data before each cut-off.

The Sensex and the Nifty 50 weigh stocks by the shares that trade, not by every share a company has issued.

How the June 2026 Reshuffle Shifts Stocks Across BSE Indexes

Angel One reports that the BSE's periodic reconstitution was set to take effect at the trading session commencing on 22 June 2026.

In the Sensex 50, TVS Motor Company replaced Adani Enterprises. In the BSE Focused IT index, L&T Technology Services replaced Cyient. Ashok Leyland was added to both the BSE 100 and the Sensex Next 50.

TVS Motor Company left the Sensex Next 50 when it moved into the Sensex 50. The BSE 100 also removed several companies, including Ambuja Cements, Tube Investments of India and Colgate-Palmolive (India).

Angel One reports no changes to the BSE Sensex or the BSE Bankex in this round.

Reading the Two Indexes Side by Side

The two indexes share a weighting method but differ in size and base year. The Sensex has 30 companies and a base value of 100 set in 1979. The Nifty 50 has 50 companies, a base value of 1,000 set in 1995, and a semi-annual review tied to 31 January and 31 July cut-offs.

Readers comparing a Nifty move with a Sensex move should note that the two indexes do not share the same constituents or base.

The level of either index on a given day reflects the free-float value of its own list of companies at that time, measured against its own base.