“We see a default as the most likely scenario,” Simon Waever, the firm’s global head of emerging-market sovereign credit strategy, wrote in a Monday note. “In case of default, it is unlikely to be like a normal one, with Venezuela instead perhaps the most relevant comparison.”

The default may come as soon as April 15, which will mark the end of a 30-day grace period on coupon payments the Russian government owes on dollar bonds due in 2023 and 2043, he said.

Indicative pricing show investors value the 2023 bonds at around 29 cents on the U.S. dollar, the lowest ever, according to data collected by Bloomberg, though there appears to have been no trades at that level. In the days before Russia invaded Ukraine last month, the debt was trading above par.

While it is rare for sovereign debt to tumble to the single digits, Morgan Stanley said Russia’s bonds “could get close.” Lebanon and Venezuela are the only recent examples of a country’s debt slipping so low.