The percentages that you should enter for your premium, your SLCSP, and your advance payment should be an amount that you and your Mom agree on. It could be 50/50, 100/0 or another amount. Make sure you are in agreement and that the percentages on all tax returns add up to 100% together. TurboTax will calculate the information that should be on your return based on your answers.
The percentages may affect your tax return if you Mom received a Premium Tax Credit toward the payment of the health insurance.
Refer to the TurboTax article I'm on my parents' 1095-A form. What do I do on my return? for further information.
Here's other articles with information regarding the Premium Tax Credit: What is the Premium Tax Credit? and When should I include Form 8962 with my tax return?
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