“비상장 주식이있었느데 올해초에 회사가 팔리면서 8천불정도 엑스트라로 소득이 발생햇는데 깜박했네요1040를 amend 해서 다시 파일링을 해야되나요?”--->Yes. You should file an amended tax return if you need to correct any piece of information that will alter your tax calculations. You can use an amended return to make corrections to your filing status, dependents, income, deductions, or tax credits. Revising your tax return is done by filing an amendment. You need to use Form 1040X, along with a new Form 1040, plus any other necessary schedules and forms. Amended tax returns have to be mailed to the IRS on paper for manual processing. The IRS typically processes an amended return about 8 to 12 weeks, but this process can take longer during the IRS's busiest times. I guess you must file amended state return, too. “Turbo tax 를 사용해서 온라인 파일링을 했는데 그걸 다시 해야되나요”--->You can’t e-file your amended return ; you need to file your amended tax return with the IRS by mailing your completed Form 1040X .Be aware that you have three years to make any corrections that result in additional tax refunds. That's because there's a three-year statute of limitations on issuing tax refund checks. This three-year period is measured from the date you filed your original tax return.