It is not uncommon to discover that an item of income was overlooked, a deduction was not claimed, or that an amended tax document was received after the tax return was already filed. Regardless of whether the oversight will result in more tax due or a refund, it should not be dismissed.
Failing to report an item of income will most certainly generate an IRS inquiry, which typically happens a year or more after the original return was filed and after the interest and penalties have built up. On the other hand, if you have a refund coming, you certainly don’t want that to go by the wayside.
The solution is to file an amended return as soon as the error or omission is discovered. Amended returns can also be used to claim overlooked credit, correct filing status or a number of dependents, report an omitted investment transaction, include items from delayed or unexpected K-1s and corrected or late filed 1099s, and account for an overlooked deduction or anything else that should have been reported on the original return. If the overlooked item will result in a tax increase, penalties, and interest can be mitigated by filing an amended return as soon as possible. Procrastination leads to further complications once the IRS determines something is missing, so it is best to take care of the issues right away.