What is the index devider used in the BSE sensex and how does the index devider derivated?

Question

Usually the sensex of BSE is calculated by taking free float market capitalization.sensex is the bench mark index derivated as
market capitalization devided by index devider. What is this index devider and which basis it is derivated?

Answer 1

The BSE Sensex or Bombay Stock Exchange Sensitive Index is a value-weighted index composed of 30 stocks with the base April 1979 = 100. It consists of the 30 largest and most actively traded stocks, representative of various sectors, on the Bombay Stock Exchange. These companies account for around one-fifth of the market capitalization of the BSE.

The base value of the Sensex is 100 on April 1, 1979 and the base year of BSE-SENSEX is 1978-79.

At irregular intervals, the Bombay Stock Exchange (BSE) authorities review and modify its composition to make sure it reflects current market conditions.

The abbreviated form "Sensex" was coined by Deepak Mohoni around 1990 while writing market analysis columns for some of the business newspapers and magazines. It gained popularity over the next year or two.

The stock market has grown by over ten times from June 1990 to today. Using information from April 1979 onwards, the long-run rate of return on the BSE Sensex can be estimated to be 0.52% per week (continuously compounded) with a standard deviation of 3.67%. This translates to 27% per annum, which translates to roughly 18% per annum after compensating for inflation.

Answer 2

SENSEX is calculated using the "Free-float Market Capitalization" methodology. As per this methodology, the level of index at any point of time reflects the Free-float market value of 30 component stocks relative to a base period. The market capitalization of a company is determined by multiplying the price of its stock by the number of shares issued by the company. This market capitalization is further multiplied by the free-float factor to determine the free-float market capitalization.

The base period of SENSEX is 1978-79 and the base value is 100 index points. This is often indicated by the notation 1978-79=100. The calculation of SENSEX involves dividing the Free-float market capitalization of 30 companies in the Index by a number called the Index Divisor. The Divisor is the only link to the original base period value of the SENSEX. It keeps the Index comparable over time and is the adjustment point for all Index adjustments arising out of corporate actions, replacement of scrips etc. During market hours, prices of the index scrips, at which latest trades are executed, are used by the trading system to calculate SENSEX every 15 seconds and disseminated in real time.
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The above is asper site of BSE-india. It involves dividing the Free-float market capitalization of 30 companies in the Index by a number called the Index Divisor.
Now what is divisor is :
In mathematics, a divisor of an integer n, also called a factor of n, is an integer which evenly divides n without leaving a remainder (refer http://en.wikipedia.org/wiki/Divisor for more details).

For strategies adopted by BSE to work out index by its Index Cell, kindly refer site : http://www.bseindia.com/about/abindices/bse30.asp

BEST OF LUCK

Answer 3

HERE IS AN EXAMPLE OF HOW ITS WORK:

Suppose the Index consists of only 2 stocks: Stock A and Stock B.

Suppose company A has 1,000 shares in total, of which 200 are held by the promoters, so that only 800 shares are available for trading to the general public. These 800 shares are the so-called 'free-floating' shares.

Similarly, company B has 2,000 shares in total, of which 1,000 are held by the promoters and the rest 1,000 are free-floating.

Now suppose the current market price of stock A is Rs 120. Thus, the 'total' market capitalisation of company A is Rs 120,000 (1,000 x 120), but its free-float market capitalisation is Rs 96,000 (800 x 120).

Similarly, suppose the current market price of stock B is Rs 200. The total market capitalisation of company B will thus be Rs 400,000 (2,000 x 200), but its free-float market cap is only Rs 200,000 (1,000 x 200).

So as of today the market capitalisation of the index (i.e. stocks A and B) is Rs 520,000 (Rs 120,000 + Rs 400,000); while the free-float market capitalisation of the index is Rs 296,000. (Rs 96,000 + Rs 200,000).

The year 1978-79 is considered the base year of the index with a value set to 100. What this means is that suppose at that time the market capitalisation of the stocks that comprised the index then was, say, 60,000 (remember at that time there may have been some other stocks in the index, not A and B, but that does not matter), then we assume that an index market cap of 60,000 is equal to an index-value of 100.

Thus the value of the index today is = 296,000 x 100/60,000 = 493.33

This is how the Sensex is calculated.

The factor 100/60000 is called index divisor.

Example (provided by rediff.com reader Munish Oberoi):
http://www.rediff.com/money/2008/feb/21bspec.htm