There has been much debate over the intentions behind Russia’s March 2022 Presential Decree requiring gas importers to settle gas payments in rubles. This column argues that the scheme is intended to protect the Moscow Stock Exchange from financial sanctions. The decree requires not only that gas payments are settled in rubles, but also that the rubles are obtained on the exchange, making it indispensable to the transactions. This prevents the exchange being placed under sanctions without gas supplies being cut off. This demonstrates the development of not only sanctions, but also sanction defences, that exploit interdependencies between countries.