What happens to my position when stocks are split.

 
Consider that I have a buying position, what happens when a stock split occurs and the price opens with a low gap?
Note: the investment is type of the CDF.
 
Seyedfazel Hosseini:
Consider that I have a buying position, what happens when a stock split occurs and the price opens with a low gap?
Note: the investment is type of the CDF.

The broker should increase your position size accordingly. If it doesn't, then contact them and demand to know why.