Have filed the last 4 years using a sibling's social security accidentally. IRS and state never notified me that 2 returns were filed with same SS#? What now?

[DianeW · Accepted solution]

It's important to correct the situation.  For this year, use the correct social security number (SSN).  You may have to mail your tax return because it's likely if you need the adjusted gross income form 2016 for verification, it will not be recognized or accepted through E-file.  You can try it if you want first, but if it rejects then file by mail. This will be an issue later as well, when the social security accounts really matter for you. Because you filed under the wrong number, your account will be short.

You can amend your return to correct the SSN and submit a copy of your social security card with the corrected Form 1040X.  Add your explanation on page 2. There will be no income changes so the results would not change, they will be able to apply all tax returns and income to the correct person for all tax years filed. Only the Form 1040X should be mailed to the IRS (the amended return is not allowed to be E-filed). See instructions below on how to amend your return.  

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