My son claimed himself without telling me. Amended my federal return. Now I owe A LOT of money. Why??

[Mike9241]

without a qualifying dependent, you go from head of household with dependent (lower tax rates and qualify for certain credits) to single (higher tax rates and may lose some credits) if all these tests are met:

the thing we can't answer because not enough information was provided is whether your son qualified to claim himself. here are the rules: 

you can claim him as a qualifying child (dependent) and he must indicate that he can be claimed as a dependent on his return if all these tests are met
• he has the same principal abode as you for more than ½ the tax year. Temporary absences like for school are ignored
• if he is not a full-time student, he's under 19 at the end of the tax year. If a full-time student, he's under 24 at the end of the tax year.
• he hasn't provided over ½ his own support
• he didn't file a joint return unless there was no tax liability but merely filed jointly to facilitate refund of taxes withheld or estimates paid

or you can claim him as a qualifying relative if all these tests are met
• his gross income for 2021 is less than $4,300
• you provided over ½ of his support
• he isn't a qualifying child of another taxpayer

if either set of tests is met he must indicate that he can be claimed as a dependent on his return which would require him to amend his return if his return was accepted.

because of the duplicate SSN one of your returns should have been rejected when an attempt was made to e-file it. 

to give the best advice as to what needs to be done we need to know if:

1) you qualify to claim him. if not, his return is fine 

2) whose return was accepted and if it was his did you mail in your original return?

[xmasbaby0]

Please explain in more detail.    How old is your son?   Was he a student in 2021?   How much income did he have in 2021?   Did you prepare a tax return claiming him as your dependent?   Was your return rejected when you tried to e-file?   What exactly do you mean when you say you "amended" your return?    Amending is a special process you only use for a return that has been filed and processed by the IRS.   Did you use that process and prepare a Form 1040X?    Or when you say you "amended" is that your way of saying you changed your return and just removed your son and now the result is that you have tax due?  Making changes to an un-filed return and "amending" are not the same thing in tax language.   

[TomD8]

The real issue here is whether your son qualified to be claimed as your dependent.  It doesn't matter if you actually claimed him or not.

If he qualified to be claimed as your dependent, then he had to indicate that on his tax return by checking the box indicating that "someone can claim you as a dependent".  If he qualified to be claimed and failed to check the box, then it's his return that's incorrect, not yours.

[VolvoGirl]

Whoa.  Why did you amend?  Did your first return go though?  Or did it get Rejected?  If you both tried to claimed him then one return should have rejected.  If it rejected you do not amend.  If one of you needs to amend you have to wait until you get the first refund to amend.  

[Opus 17]

Without comparing tax returns, we don't know exactly what changed.  If you claimed a recovery rebate ($1400) because you did not get a round 3 stimulus, that would have been removed. You would lose the $500 credit for other dependent or up to $3000 child tax credit, depending on his age.  You might have lost head of household status and reverted to single, which has higher tax rates overall. 

The real question is whether your son can be independent.  He must answer "yes I can be claimed as a dependent by someone else" if he can be claimed, even if he does not want to be claimed. If he answers "No, I can't be claimed as a dependent by someone else" when he actually can be, that might be tax fraud and financial aid fraud.   If he can be claimed, you don't have to amend.  The IRS will investigate and he will be forced to amend.  Or, you can let it go and not raise a fuss, in which case you have to amend and pay the extra tax.