They are taxable (assuming they turn into stock appreciation which ASML has not been great at for a while) but at a lower capital gains rate.
In the Netherlands, appreciation is immediately taxable for individuals, but not for corporations.
I presume you don't send a cheque off for €1.36 at the end of the day, (or receive a cheque back after 8 months)
Of course this state of affairs relies on companies not all jumping to stock buybacks, or else the treasury will find some new way of getting their pound of flesh