The custodial parent has first
priority on claiming the children on her taxes; regardless of the amount of
support provided by the non-custodial parent. The
IRS goes by physical custody, not legal custody. The non-custodial parent
can only claim the child as a dependent if the custodial parent gives permission
(on form 8332) or if it's spelled out in a pre 2009 divorce decree. Even if a divorce decree, dated after 2008, gives the non-custodial parent the
right to claim the child, he must still get form 8332 from the custodial parent.
A properly worded decree should require her to provide that form. https://www.irs.gov/pub/irs-pdf/f8332.pdf
There is a way to split the tax benefits. For future negotiations with the
other parent (and maybe even for this year) the following info may be of use:
There is a
special rule in the case of divorced & separated (including never married) parents.
When the non-custodial parent is claiming the child as a dependent/exemption/child
tax credit; the custodial parent is still allowed to claim the same child for Earned
Income Credit, Head of Household filing status, and day care credit. This
"splitting of the child" is not available to parents who lived
together at any time during the last 6 months of the year; then only one of you
can claim the child for any tax reasons. The tax benefits may not be split in any
other manner.
Note in particular
that the non-custodial parent can never claim the Earned Income Credit, Head of
Household filing status or the day care credit, based on that child, even when the custodial parent has released
the exemption to him.
So, it's good idea to let the other parent know that you
will be claiming those items, as many first time divorced parents are not aware
of this rule and may try to claim those items, which will cause the IRS to send
out letters.
Ref: https://www.irs.gov/publications/p17#en_US_2017_publink1000170897
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