Over the past few years, wealth taxes have reentered public debate. Popular economists like Gary Stevenson, Grace Blakely and Faiza Shaheen, and now political leaders like Zack Polanski, argue that the UK must tax the richest more aggressively if it hopes to repair crumbling public services and address spiralling inequality. They’ve managed to persuade 68% of the public. But the wealth tax debate often misses a crucial problem. Wealth today does not simply sit inside national borders, waiting to be taxed. It moves; it hides.