If you sold your interest in the property for less than its FMV as of the date of sale, then you've given your sibling a gift of equity, which requires filing a gift tax return (IRS Form 709) if the amount of the gift exceeds the current annual gift tax exclusion amount ($18,000 in 2024). The gift is the amount between the FMV of your interest in the property and the price you received.
If you sold your interest in the property for less than your adjusted cost basis, then you have a capital loss.
If the property was not used as rental, investment or business property during your time of ownership, then the property is considered personal-use property and your capital loss would not be deductible, nor would it be eligible for the $3,000 annual capital loss carryover. In that case it is not necessary to report the loss on your income tax return.
https://www.freetaxusa.com/answers?faq=10581
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
