Which Parent's Return To Use IRS Pub. If a child's parents are married to each other and file a joint return, use the joint return to figure the tax on the investment income of a child under 14. For parents who do not file a joint return, the following discussions explain which parent's tax return must be used to figure the tax. Only the parent whose tax return is used can make the election described under Parent's Election To Report Child's Interest and Dividends.
Parents are married.
If the child's parents file separate returns, use the return of the parent with the greater taxable income. Parents not living together. If the custodial parent is not considered unmarried, use the return of the parent with the greater taxable income. For an explanation of when a married person living apart from his or her spouse is considered unmarried, see Head of Household in chapter 2. Parents are divorced.