The 1099INT will come with one ssn on it. They can report 100% on their return or you can split it up. Whoever's ssn is on the 1099 enters the whole amount on their return. Then after you enter it, on the next page it will ask - Tell us if any of these uncommon situations Apply and pick the first one, We need to adjust the taxable amount.
Then on the next page fill in their amount as a POSITIVE number and pick the first reason "I received all or part of this for someone else".
Then on the other person's return you enter it as a 1099 Int and put their amount in box 1.
