If an amended return is based on a non-business bad debt or worthless security how many years?

If an amended return is based on a non-business bad debt or worthless security, you generally have three years from the due date of the original return to file the amended return. This timeline follows the standard rule for claiming a refund or correcting errors. However, for worthless securities, you must also ensure that the security was indeed worthless by the end of the tax year in which you claim the deduction. Always consult with a tax professional for specific circumstances.