G20 hears a $250-billion-a-year idea: tax the super-rich

French economist Gabriel Zucman brought a $250-billion-a-year idea to top policy makers from the world’s biggest economies Thursday: slap an international wealth tax on the super-rich.

Zucman, a 37-year-old ex-protege of renowned economist and inequality expert Thomas Piketty, was invited to outline his research on tax evasion by the ultra-wealthy at a meeting of finance ministers from the Group of 20 nations, which is working to address the issue.