Actually, this is nonsense. Russian elites are far more concerned about the fact that when we add up the value of the hundreds of billions of "private" -- eg mostly stolen -- flight capital that has poured out of Russia since the early 1990s, Russia's foreign "flight wealth" is more than $900 billion. This dwarfs even the $538b of official Russian gross reserves, much less the mere $116b on net foreign reserves that's left over when you net out Russia's $422b gross external debt. So the oligarchs are literally shitting themselves over the chance that such funds might face a variety of Western sanction if this continues to escalate. Furthermore, while the Russian gov is a net lender to the West (after reserves), many corporations have become huge net borrowers. They are very vulnerable to a freeze on new finance. As for foreign direct equity finance, Russia has not been a very easy place to invest for mos Western countries, so it is correspondingly not very vulnerable there. But if we wanted to make the Russian economy "scream," freezing new loans and the repatriation of private foreign assets, including real estate and private yachts as well as bank accounts and trusts and Russian(Putin)- owned Swiss trading companies pending "careful investigations of their true ownership, tax and business practices" would be one way to bring this outrageous New Tsar to his knees.
True, Western Europe still gets 30% of its energy from Russia, and its banks (especially Austria, Italy, Greece, Portugal, and, indirectly, Germany) have loaned Russia, Ukraine, and Ukraine's neighbors a fortune. But with economic growth already falling to 1% before this crisis! Russia can't really afford not to export the energy, and it is desperate for foreign finance in part because its elite takes the money out and pays so little tax.
So oligarchs are right now selling their foreign shares, scrambling to cover their loans, and watching like deer in the headlights as the ruble and the value of their domestic wealth plummet by billions. They have got to be thinking: Putin has lost his mind, My own prediction if he doesn't back off (and he really does have many ways to do so): Putin may well have just made a mistake the size of his life;