No, you do not have to re-file both returns.
Joint account earnings can be split 50/50 or in whichever proportions as the joint account holders agree.
If you report 100% of the capital gains, then your son does not report anything on his tax return.
Your son can write to the IRS stating that all gains have been reported by you.
There should be a primary SSN that the account is associated with, and IRS will match that with whoever's SSN it is. So whoever's return it goes on, or does not go on, make sure 100% is reported to IRS between the two returns. Also due to IRS matching this document, you may get a letter a year or two and may have to explain to them, how it was reported. So keep the tax documents in your tax records for at least 3 years.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
