When a child has investment income — from a UTMA account, an inheritance, or a trust — their return is often far more complex than it appears, and the kiddie tax rules can significantly affect the family's overall tax picture.
A dependent child must file a tax return if their unearned income (investment income) exceeds $1,300 in 2026, or if their earned income exceeds the standard deduction for dependents. Many families are surprised to learn that a child with a modest UTMA account or an inherited investment portfolio may have a filing obligation every year.
The kiddie tax rules exist to prevent high-income parents from shifting investment income to their children to take advantage of lower tax rates. Under these rules, a child's unearned income above $2,600 in 2026 is taxed at the parent's marginal rate — not the child's rate.
The kiddie tax applies to children under age 18, children age 18 whose earned income doesn't exceed half their support, and full-time students ages 19–23 in the same situation. When the kiddie tax applies, Form 8615 must be attached to the child's return, and the parent's tax information is required to calculate the child's tax — creating an interdependency between both returns.
Income from custodial investment accounts — dividends, interest, capital gains distributions — is taxable to the child and subject to the kiddie tax rules. When the child reaches the age of majority and the account transfers to them outright, there may be additional tax considerations around the transfer.
Children who inherit assets — directly or through a trust — may receive K-1s from the estate or trust, or may hold inherited investments directly. The same stepped-up basis rules apply, and the kiddie tax rules apply to any income those inherited assets generate.
In some cases, parents may elect to report a child's investment income directly on their own return using Form 8814 (Election To Report Child's Interest and Dividends), rather than filing a separate return for the child. This eliminates the need for a separate filing but may result in higher overall tax — particularly when state tax rules or the kiddie tax calculation are involved. Some states also have their own version of this election, or specific rules around when the parent election is and isn't advantageous. We evaluate both options and recommend the approach that results in the lowest total family tax burden across federal and applicable state returns.