Kindly Reminder: a final peek on your W-2
pls check it closely to make sure everything is up to year-end. e.g. company stock option (ISO, NON-QUAL and RSU, even w/ ESPP). sometimes, employer just put proceeds into box 1 of W-2 and omitted any taxes you have already paid - tax withheld on box 2, 4, 6 and 17 of w-2, repectively. this will result in double taxes on your stock option selling.
get it check out and amend your w-2 in time. or you have to file 1040X later.
Happy filing!