These accounts are certainly not perfect. For example, at the world level, the net financial position is negative overall, which is logically impossible unless we assume that on average we’re owned by the planet Mars. More likely, this contradiction suggests that a nonnegligible share of financial assets held in tax havens and by nonresidents is not correctly reported as such. Among other things, this affects the net external position of the Eurozone, which is probably much more positive than official statistics suggest, as the economist Gabriel Zucman has recently shown. Well-off Europeans have every interest in hiding assets, and the European Union for the moment isn’t doing what it should—and could—to deter them.