Buried in Trump's new tax bill is a 5% tax on remittances that only applies to non-U.S. citizens. Forgetting the concerns around equity and fairness for a second, such a tax would add an incredible amount of complexity to an already convoluted system. Not only would firms need to report to a central administration, they would have to start tracking data points such as citizenship status and recipient location. It also raises the technical question: What is a remittance, anyway?