1. What is the base year and base value used for calculating the Sensex?

The base period for the calculation of the BSE Sensex is the financial year of 1978-79. The base index value has been 100 points, and the base market capitalisation has been fixed at Rs. 25014.24 crores.

2. How frequently does the BSE revise the Sensex 30 list?

The constituents of Sensex are reviewed on a semi-annual (twice a year) basis in June and December by the S&P BSE Index Committee. Companies that cease to meet the strict liquidity, market cap, or sector representation criteria are removed and replaced by eligible and highly-performing emerging companies.

3. What is the difference between Sensex and Nifty?

While both are benchmark indices of the Indian stock market, Sensex is the proprietary index of the Bombay Stock Exchange (BSE) and comprises 30 large-cap companies. On the other hand, Nifty (or Nifty 50) is the benchmark index of the National Stock Exchange (NSE) and tracks the performance of the top 50 large-cap companies .

4. Can I invest directly in the Sensex?

No, you can not directly invest in the Sensex as it is just an index and not a tradable asset in itself. However, you can invest in the Sensex indirectly, via investing in a Sensex Index Mutual Fund or a Sensex Exchange Trading Fund (ETF), which pools funds from several investors to buy the same 30 stocks, in the same proportion as the Sensex.

5. Why does the Sensex value change every single second?

The Sensex value is calculated in real-time on the basis of the live trading prices of its 30 constituent stocks. As millions of buyers and sellers buy and sell these shares continuously from one another during market hours, their stock prices rapidly fluctuate. This, in turn, alters their free float market capitalisation, which results in altering the overall Sensex points every second.