SET50 Index and SET100 Index

To accommodate the issuing of index futures and options in the future, and to provide a benchmark of investment in The Stock Exchange of Thailand, the SET50 Index and the SET100 Index were launched. Both indices are calculated from the stock prices of the top 50 and 100 listed companies in The SET in terms of large market capitalization, high liquidity and comply with the requirement regarding the distribution of shares to minor shareholders, and etc. The calculation method, used for these two indices, is the same as that used for the SET Index which is a market capitalization weighted index. The base dates used are August 16, 1995 (SET50 Index) and April 30, 2005 (SET100 Index), which are the respective dates when the two indices were established and set at 1000 points. The base market value is continually adjusted to correspond to changes in the values of securities resulting from changes in the number of stocks due to various events; such as public offerings, exercised warrants, conversions of preferred to common shares, and etc.

Stock Revision

The list of component stocks in the SET50 Index and the SET100 Index are revised every 6 months in order to adjust for any unexpected changes that have occurred in the stock market such as new listings or public offerings. After these adjustments are made, stocks that meet the necessary qualifications are then selected to become part of the SET50 Index or the SET100 Index. Stock selection is conducted semi-annually between December 1 - 31 and June 1 - 30. During these two periods, The Stock Exchange of Thailand will select stocks based on its pre-stipulated criteria. The revised stock lists for both the SET50 and the SET100 will be announced to the general public as soon as the lists become available. New SET100 and SET50 Indices will take affect on the first trading day in January and July of each year. For every revision, both Index calculations will treat stocks which have been withdrawn as a delisting case and stocks which have been added as a new listing case. Whenever a stock is removed from either or both of the indices, a new stock will be added to replace it and to ensure the uninterruption of the indices. Also, adjustments will be made whenever the market value of a component stock changes due to the conversion of convertible bonds, the exercising of warrants, or new shares are issued for capital increase of the component stock, etc.