We propose to institute a new annual tax of 0.2% on corporations’ stock shares for all publicly listed companies headquartered in G20 countries. As the G20 stock market capitalization is around US$ 90 trillion, the tax would raise approximately US$ 180 billion each year. Because stock ownership is highly concentrated among the rich, this global tax would be progressive. The tax could be paid in-kind by corporations (by issuing new stock) so that the tax does not raise liquidity issues for new and innovative firms, nor does it affect business operations. The tax could be enforced by the securities commissions in each country, which already regulate publicly traded securities.