Stuck in a recession and with no sign of a reprieve in the oil price, Russia could quickly descend into chaos if the money runs out, William Browder, a well-known critic of the Kremlin and chief executive of Hermitage Capital, told CNBC.
"I don't think you can underestimate how bad the situation in Russia is right now, you've got oil below any measure where the budget can survive and you've got sanctions from the West. Russia is in what I'd call a real serious economic crisis," he said on Thursday.
Speaking to CNBC in Davos where global business and political leaders are attending the World Economic Forum (WEF), Browder said the central bank of Russia was "running out of money."
"Let's say that they have $200 billion (in reserve) and they're burning through all sorts of money right now because of the oil prices and sanctions. They just don't have the money to support the ruble and so Russians are just suffering," he said, adding.
"Eventually they're going to run out of that money and when they do, that's when the real trouble begins," he added.
His comments come as the ruble continued its slide against the dollar. On Thursday it hit 85 rubles per dollar.
Browder was a one-time fan of Russian President Vladimir Putin but he became one of the Kremlin's biggest critics following the death of his lawyer and friend Sergei Magnitsky, who was found dead while in police custody in 2009.
Browder believes the Russian authorities were responsible for the death of Magnitsky, who had been investigating corruption among Russian officials before his death. Browder also wants an international investigation into the killing of Russian opposition figure Boris Nemtsov. Browder himself was expelled from Russia in 2005 after criticizing alleged endemic corruption in the country.
As such, Browder is certainly no friend of the Russian regime and in 2013,he told CNBC that he felt under threat.
Russia entered recession in 2015 following the dramatic decline in global oil prices (Russia is a major oil producer) as well as international sanctions imposed on it for its annexation of Crimea in March 2014 and role in the pro-Russian uprising in Ukraine in the same year.
On Tuesday, the International Monetary Fund (IMF) cut its growth forecast for Russia in 2016, predicting that the economy would contract by 1 percent, worse than the 0.6 percent contraction predicted by the IMF in October.
Concerns over Russia have manifested themselves in Russian markets which have continued to experience tumult since the start of the year. The ruble has also continued its slide against the dollar, falling a further 8 percent since the start of the year to currently trade around 81 rubles to the dollar.
The economic crisis had caused Putin to create a nationalist regime and foreign enemy in the West, Browder told CNBC, and to oversee what he called "repression" within Russia.
Browder's hedge fund has traditionally focused on emerging markets but he warned that former economic powerhouses such as Russia and Brazil, as well as still relatively robust China, were in turmoil, as market and currency turbulence has recently shown.
"There's a mess in Brazil, there's a mess in China, there's a mess in Russia, there's a mess everywhere, and I would say that having seen this play out before, were nowhere near the point where you want to step in."
"Having said that, as an investor, I like things cheaper rather than more expensive so at some point it's going to be worth bottom-picking."
Follow CNBC International on and Facebook.