Lenders doing business with Russia often conduct transactions in dollars or euros specifically because Moscow’s economy is more volatile and emerging. But President Vladimir Putin has said his government could force lenders in certain countries to accept only Russian currency; as of Wednesday afternoon, the exchange rate was 120 rubles to $1. The Kremlin also has barred its citizens from withdrawing more than $10,000 in hard currency from the nation’s banks.

Now, experts say, Russia is running out of dollars and other standard global currencies with which to pay creditors, and covering debts with rubles could only serve to further devalue the currency because it basically worthless in global markets.

Western energy sanctions — President Biden said the United States would stop importing Russian fossil fuels, and the European Union said it would cut its consumption by two-thirds this year — issued in response to Putin’s invasion of Ukraine also serve to starve the Russian economy of new revenue. That means injections of even rubles into its domestic economy could be hard to come by.

Inside Russia, a default would mean tremendous economic hardship for ordinary people.