Normally my ex claims my son as a dependent although he lives with me full time. That's just how we set it up when we divorced, he claims one I claim one. However, this year (2020 taxes) he did not claim him for whatever reason. My son is 18 so he was excluded from the last 2 stimulus payments anyways. However, this one he is able to receive. So my question is do I need to amend my return to add him as a dependent for him to receive it; or do I need to file 2020 taxes strictly for him with 0 income for him to receive it? I cannot seem to find any information online to help me determine which route I need to go. Since mine were already filed, approved and refund received I would have to amend mine. I just don't want to mess it up for him to receive it.
Adding your son to your return as a dependent won't qualify him for the first and second stimulus payments. Only dependent children under 17 years old are eligible for the additional $600 stimulus payment to the taxpayer claiming them on their taxes. Any 17-24 years children claiming as dependents are not eligible for first two stimulus payments.
You might want to amend your return. Adding him as a dependent will give you agitational tax credit for other dependent and potentially could put your in a different tax bracket. The only concern, to process amended returns usually takes time, and the IRS could finish the third rounds of stimulus checks by the time they will process your amended tax return. If your ex-husband claimed him as a dependent in 2019, the IRS could use 2019 information and send the payment for your son to you ex-husband. You also can file your son return with 0 income and mark there he's a dependent. It is hard to tell if it helps, it could.