on the first listed SSN in their return enter the gross interest
the 2024 interest income section is currently unavailable so I don't know if the procedure will change for 2024
in 2023 you'll come to a page that states "I need to adjust the taxable amount" this needs to be checked.
the next page. "check I received some or all of the interest for someone else" enter the other party's amount where indicated. enter as a positive number
schedule b will show the gross and a subtraction for the nominee amount.
the other party? i'm not sure whether they need to follow the above or just enter their portion.
