Concept:
Free-float Methodology refers to an index construction methodology that takes into consideration only the free-float market capitalization of a company for the purpose of index calculation and assigning weight to stocks in Index. Free-float market capitalization is defined as that proportion of total shares issued by the company that are readily available for trading in the market. It generally excludes promoters' holding, government holding, strategic holding and other locked-in shares that will not come to the market for trading in the normal course. In other words, the market capitalization of each company in a Free-float index is reduced to the extent of its readily available shares in the market.
In India, BSE pioneered the concept of Free-float by launching BSE TECk in July 2001 and BANKEX in June 2003. While BSE TECk Index is a TMT benchmark, BANKEX is positioned as a benchmark for the banking sector stocks. SENSEX becomes the third index in India to be based on the globally accepted Free-float Methodology.
Major advantages of Free-float Methodology:
Definition of Free-float:
Share holdings held by investors that would not, in the normal course come into the open market for trading are treated as ‘Controlling/ Strategic Holdings' and hence not included in free-float. In specific, the following categories of holding are generally excluded from the definition of Free-float:
The remaining shareholders would fall under the Free-float category.
Determining Free-float factors of companies:
BSE has designed a Free-float format, which is filled and submitted by all index companies on a quarterly basis with the Exchange. (Format available on www.bseindia.com) The Exchange determines the Free-float factor for each company based on the detailed information submitted by the companies in the prescribed format. Free-float factor is a multiple with which the total market capitalization of a company is adjusted to arrive at the Free-float market capitalization. Once the Free-float of a company is determined, it is rounded-off to the higher multiple of 5 and each company is categorized into one of the 20 bands given below. A Free-float factor of say 0.55 means that only 55% of the market capitalization of the company will be considered for index calculation.
Understanding Free-float Methodology
1.4 Maintenance of SENSEX
One of the important aspects of maintaining continuity with the past is to update the base year average. The base year value adjustment ensures that replacement of stocks in Index, additional issue of capital and other corporate announcements like ‘rights issue' etc. do not destroy the historical value of the index. The beauty of maintenance lies in the fact that adjustments for corporate actions in the Index should not per se affect the index values.
The Index Cell of the exchange does the day-to-day maintenance of the index within the broad index policy framework set by the Index Committee. The Index Cell ensures that SENSEX and all the other BSE indices maintain their benchmark properties by striking a delicate balance between frequent replacements in index and maintaining its historical continuity. The Index Committee of the Exchange comprises of experts on capital markets from all major market segments. They include Academicians, Fund-managers from leading Mutual Funds, Finance-Journalists, Market Participants, Independent Governing Board members, and Exchange administration.
1.4.1 On-Line Computation of the Index:
During market hours, prices of the index scripts, at which trades are executed, are automatically used by the trading computer to calculate the SENSEX every 15 seconds and continuously updated on all trading workstations connected to the BSE trading computer in real time.
1.4.2 Adjustment for Bonus, Rights and Newly issued Capital:
The arithmetic calculation involved in calculating SENSEX is simple, but problem arises when one of the component stocks pays a bonus or issues rights shares. If no adjustments were made, a discontinuity would arise between the current value of the index and its previous value despite the non-occurrence of any economic activity of substance. At the Index Cell of the Exchange, the base value is adjusted, which is used to alter market capitalization of the component stocks to arrive at the SENSEX value.
The Index Cell of the Exchange keeps a close watch on the events that might affect the index on a regular basis and carries out daily maintenance of all the 14 Indices.
When a company, included in the compilation of the index, issues right shares, the free-float market capitalisation of that company is increased by the number of additional shares issued based on the theoretical (ex-right) price. An offsetting or proportionate adjustment is then made to the Base Market Capitalisation (see ‘Base Market Capitalisation Adjustment' below).
When a company, included in the compilation of the index, issues bonus shares, the market capitalisation of that company does not undergo any change. Therefore, there is no change in the Base Market Capitalisation, only the ‘number of shares' in the formula is updated.
Base Market Capitalisation Adjustment is required when new shares are issued by way of conversion of debentures, mergers, spin-offs etc. or when equity is reduced by way of buy-back of shares, corporate restructuring etc.
1.5 SENSEX - Script selection criteria
The general guidelines for selection of constituents in SENSEX are as follows:
Quantitative Criteria:
Market Capitalization:
The script should figure in the top 100 companies listed by market capitalization. Also market capitalization of each script should be more than 0.5 % of the total market capitalization of the Index i.e. the minimum weight should be 0.5 %. Since the SENSEX is a market capitalization weighted index, this is one of the primary criteria for script selection. (Market Capitalization would be averaged for last six months)
Liquidity:
Trading Frequency: The script should have been traded on each and every trading day for the last one year. Exceptions can be made for extreme reasons like script suspension etc. (ii) Number of Trades: Number of Trades: The script should be among the top 150 companies listed by average number of trades per day for the last one year. (iii) Value of Shares Traded: Value of Shares Traded: The script should be among the top 150 companies listed by average value of shares traded per day for the last one year.
Continuity:
Whenever the composition of the index is changed, the continuity of historical series of index values is re-established by correlating the value of the revised index to the old index (index before revision). The back calculation over the last one-year period is carried out and correlation of the revised index to the old index should not be less than 0.98. This ensures that the historical continuity of the index is maintained.
Industry Representation:
Script selection would take into account a balanced representation of the listed companies in the universe of BSE. The index companies should be leaders in their industry group.
Listed History:
The script should have a listing history of at least one year on BSE.
1.5.2 Qualitative Criteria:
Track Record:
In the opinion of the Index Committee, the company should have an acceptable track record.
Index Review Frequency:
The Index Committee meets every quarter to discuss index related issues. In case of a revision in the Index constituents, the announcement of the incoming and outgoing scripts is made six weeks in advance of the actual implementation of the revision of the Index.
1.6 Beta of SENSEX
Beta measures the sensitivity of a script movement relative to movement in the benchmark index i.e. SENSEX. A Beta of one means that for every change of 1% in index, the script moves by 1%. Statistically Beta is defined as: Covariance (SENSEX, Stock )/ Variance(SENSEX)
Note: Covariance and variance are calculated from the Daily Returns data of the SENSEX and SENSEX scripts.
1.7 The closing Index
The closing SENSEX is computed taking the weighted average of all the trades on SENSEX constituents in the last 15 minutes of trading session. If a SENSEX constituent has not traded in the last 15 minutes, the last traded price is taken for computation of the Index closure. If a SENSEX constituent has not traded at all in a day, then its last day's closing price is taken for computation of Index closure. The use of Index Closure Algorithm prevents any intentional manipulation of the closing index value.
SENSEX Milestones
The SENSEX crossed the 1,000 mark on July 25, 1990; the 2,000 mark on January 15, 1992; the 3,000 mark on February 29, 1992; the 4,000 mark on March 30, 1992; the 5,000 mark on October 11, 1999; the 6,000 mark on January 2, 2004; the 7,000 mark on June 21, 2005; the 8,000 mark on September 8, 2005; the 9,000 mark on December 09, 2005; and finally the historic 10,000 mark on February 7, 2006. It created another landmark when it touched 11,000 on March 27, 2006. The SENSEX closed at a high of 12,903 on 28 Oct 2006. To reach from the 11,000 mark to the 12,000 mark only took 19 working days, the shortest time interval for a 1000 points climb in BSE SENSEX history, surpassing the just set record of 29 days that it took to reach 11,000 from 10,000.
Here is a timeline on the rise and rise of the SENSEX through Indian stock market history.
On May 22, 2006, the SENSEX plunged by a whopping 1100 points during intra-day trading, leading to the suspension of trading for the first time since May 17, 2004. The volatility of the SENSEX had caused investors to lose Rs 6 lakh crore ($131 billion) within seven trading sessions. The Finance Minister of India, P. Chidambaram, made an unscheduled press statement when trading was suspended to assure investors that nothing was wrong with the fundamentals of the economy, and advised retail investors to stay invested. When trading resumed after the reassurances of the Reserve Bank of India and the Securities and Exchange Board of India, the SENSEX managed to move up 700 points, still 450 points in the red. This is the largest ever intra-day crash (in points terms) in the history of the SENSEX.
The SENSEX eventually recovered from the volatility, and on October 16, 2006, the SENSEX closed at an all-time high of 12,928.18 with an intra-day high of 12,953.76. This was a result of increased confidence in the economy and reports that India's manufacturing sector grew by 11.1% in August 2006.
