She said: “They’re not rated by the agencies as a selective default yet, but mighty close.”
Althea Spinozzi, a fixed rates strategist at Saxo Bank, said it was possible that Russia could default “as soon as next week”.
Defaulting would mean Moscow would be ostracised on global debt markets.
This would leave it unable to request money from Western investors.
Sanctions are likely to place the economy into steep contraction and the stock markets have remained shut.
Since the invasion of Ukraine, the ruble has collapsed in value.
Kristalina Georgieva, managing director of the International Monetary Fund (IMF), said that Russia is facing a “deep recession” from sanctions.
Access has also been cut to central bank reserves, reducing living standards and sparked an exodus of Western businesses.
She added that global growth forecasts are likely to be cut as a result of the crisis.
It comes as Russian foreign minister Anton Siluanov said on Thursday that Russia would make foreign debt payments to Western countries in rubles.
This is likely to be unpalatable to Western investors who usually want payment in the same currency they bought their bonds typically Dollars, Pounds or Euro and could be considered a default.