For the floor and ceiling price limits, the SET sets the floor limit at a minus 30% of the previous day's closing price on the main board while the ceiling limit at a plus 30% of the previous day's closing price on the main board. However, for securities which the prices are less than one baht, stock prices can fluctuate freely. Ceiling and floor limits are applied to each trading board except for the foreign board.
Warrant / Derivative Warrant can increase the value 30% maximum of stock value multiple by right to buy stock or unit trust.
When company decide to pay dividend, the calculation of highest and lowest price for the first date of XD can find by deduction of dividend payment and calculate the highest and lowest price related to new closing price.
In case of XR, the calculation of highest and lowest price of the first date of XR can get by find the weight average of previous closing price and exercise price which are amount of current stock and amount of new stock, then calculate the highest and lowest from new closing price.