English to French Bus/Financial Finance (general) Award Agreement (Bank)

Good evening, I am looking for a translation of the word 'discount' in the above which would not sound like 'cheap' - rabais, réduction -:((....
The context : this is about a stock option program for staff - the text makes a difference between some shares or units which are 'base shares' and other ones which are 'discount stock units'. Any help greatly appreciated. Thanks in advance