It’s 2 a.m. at La Factoria in Puerto Rico’s Old San Juan, a hipster joint with a sagging couch, tile floors and Christmas lights that wouldn’t be out of place in Brooklyn’s Williamsburg. While “Get Lucky” plays, tipsy couples slink out the doors onto the colonial city’s cobblestone streets into this warm April night.

At the bar, a 28-year-old hedge fund trader—the type of person who posts his SAT results on his LinkedIn page—is ranting about the tax code. He’s obsessed with it, complaining that the U.S. is the only major country taxing citizens on their worldwide income, no matter where they reside. That’s why he moved here.