I highly appreciate the insightful responses. This gave me a real relief. Just for confirmation purposes: Neither I nor my wife did not violate any IRS/IRC/tax law due to this $25,000 loan transactions and that we do not need to report this matter to IRS/IRC/tax agency in the future as well. Please let me know if I am incorrect.
Unfortunately, my issue is not yet over: I have two children.
(ii). For my other child, Joshua, I gave $9,500 loan with 0% interest (we have loan agreement and we cannot say that it is a gift) for his college fee and for application fee for graduate schools, cell phone, etc. during 2016. Joshua did not pay any money back to me in 2016 but paid part of the loan in 2017 and is planning to pay the remaining amount in 2018.
I’m starting with Joshua here because that’s the easier of the two. Under IRC § 7872(c)(2)(A) if the total of the below market loans between you and the other person amount to no more than $10,000 the imputed interest rules will not apply. So if your only below interest loan made by you and/or your wife (since the two of you are treated as one person for the imputation rules) to Joshua was this loan for $9,500 then the interest imputation rules will not apply and you have no income from the loan to report.
Now to the loan for John:
(i). For one of my children, John, I gave $14,500 loan with 0% interest (we have loan agreement and we cannot say that it is a gift) for his college fee and car during early 2016. John paid part of that amount during 2016 without any interest. He paid me back the remaining money in 2017 without interest.
This loan did exceed $10,000 and thus for at least 2016 you need to consider the interest imputation rules. If he paid off enough of the loan in 2016 to bring the balance under $10,000 then there won’t be any imputed interest in 2017. For 2016 (and in 2017 if the balance owed was more than $10,000 on any day in 2017) you have to determine what the imputed interest is. That amount of imputed interest is then treated as though you gave that amount of money to John as a gift on 12/31/16 and then that same day John transferred that amount back to you as a payment of interest.
Now, it gets a bit more complicated from here because of a special rule. The special rule is that for income tax purposes the amount of imputed interest John paid you is limited to John’s net investment interest for the year. So if his net investment interest was zero, then there is no imputed interest to include on your return. (Note that this limitation on the imputed interest does not apply if the total loans between you and the borrower exceed $100,000 or if the purpose of the loan was tax avoidance, neither of which seems applicable here). A second special rule says that if John’s net investment income does not exceed $1,000 then his net investment income for the purpose of the imputed interest rule is considered to be zero.
So, if John had $1,000 or less of net investment income then there is no imputed interest received by you and there is nothing you need to do with your 2016 return. If John had more than $1,000 of net investment income then you have imputed interest income from the loan and may need to amend your return to include it. That amount of imputed interest will be quite low, so it may make little, if any, difference in your tax. There would almost certainly be no penalty for this given the small amount of that would be involved.
Now, the net investment limitation rule I discussed above only applies for income tax. It does not apply for gift tax. Thus, you are considered to have made a gift to John on 12/31/16 in the amount of the imputed interest. If that gift along with all the other gifts you gave him during the year totaled more than $14,000 then you were required to file a federal gift tax return. Otherwise, the gift part of this is not an issue for you. Even if you have to file the gift tax return you still do not owe any actual gift tax unless you have given away well more than $5 million in taxable gifts over your lifetime.
Note that even if you had imputed interest income you were not required to issue any Forms 1098 or 1099.
So at worst you may need to amend your 2016 return to include a small bit of imputed interest income and might (if you gave anyone gifts totaling $14,000 or more during the year) file a gift tax return. This is not, however, something you should stress much over.