We consider introducing an expiry date for offline digital currency balances. Consumers whose digital cash expired would automatically receive the funds back into their online account. This functionality could increase demand for digital cash, with the time to expiry playing a key role.
One argument for central bank digital currencies (CBDCs) is that without them, private and foreign digital monies could displace domestic currencies, threatening the central bank’s monetary policy and lender of last resort capabilities. I revisit this monetary sovereignty rationale and offer a wider view—one that considers a broader set of currency functions and captures important cross-country variation.