Once upon a time, some parents and grandparents would attempt to save tax by putting investments in the names of their young children or grandchildren in lower income tax brackets. To discourage such strategies, Congress created the “kiddie” tax back in 1986. Since then, this tax has gradually become more far-reaching. Now, under the Tax Cuts and Jobs Act (TCJA), the kiddie tax has become more dangerous than ever. A short history Years ago, the kiddie tax applied only to children under age 14 — which still provided families with ample opportunity to enjoy significant tax savings from income shifting. In 2006, the tax was expanded to children under age 18. And since 2008, the kiddie tax has generally applied to children under age 19 and to...