e.g. you actually paid for $10/sh while mkt price is $40.
your actual cost = 200*10=2000
w-2 income = (40-10)X200=6000, reported in your box 1 of w-2. in another word, 6000 is not your basis. it's
your W-2 income earned from your purchase discount.
you sold it later for more than $40/shr, say $45/shr, your proceeds is 45*200=9000.
8494 of sch D.
I am not tax professional. reference only.