Bonus Issue Not Reflected in Prices

#1
I downloaded corp action from nseindia.com to look for splits and bonus issues, but apparently many in many scrips, there is no change in price on the day of bonus issues (ex date) even in the case 1:1 split. Here are some examples

3IINFOTECH 28/08/2007 - - BONUS 1:1
GEMINI 17/07/2007 - - BONUS 1:1
JBMA 24/10/2007 - - BONUS 1:2

Could someone please explain this, why there is no price change in the scrips on ex date.
 

Similar threads