Bombay Stock Exchange (BSE) introduced new index called BSE MID-Cap index to track the performance of companies with relatively mid-size market capitalization.
BSE-500 Index - represents more than 93% of market cap of the listed companies in Bombay Stock Exchange (BSE). Companies with large market capitalization bias the movement of BSE-500 index. This created a need to create a separate indicator to capture the trend in companies with mid-size market capitalization. Over the years, BSE Mid-Cap have proven to be a great use to the investing community.
BSE Mid-Cap index is launched in April 2005 and uses base year of 2002-2003 for index calculations with base value of 1000. It is based on free-float methodology. The index is constructed on 80%-15%-5% method whereby companies aggregating 98.5% of average market capitalization are categorized under large, mid and small cap segment respectively. BSE Mid-Cap tracks the performance of stocks between 80 & 95% of aggregate market capitalization. The total number of companies in the index is variable. BSE Mid-Cap index is highly correlated with BSE-500 index. Companies in this index are reviewed on a quarterly basis.
Base Market capitalization Adjustment
The formula for adjusting the Base Market capitalization is:
New Base Market capitalization = Old Base Market capitalization * (New Market capitalization / Old Market capitalization)
The closing index value is calculated as weighted average of all the trades of index stocks in the last 30 minutes of trading session. If an index stock has not traded in the last 30 minutes, the last traded price is taken used for index calculations. If an index company has not traded at all in a day, then its last day's closing price used for calculations. The use of index closure calculation avoids any intentional manipulation of the closing index value.
Revised on April 13, 2009 and Free-Float Adjustment Factor revised on May 25, 2009