Russia’s elite class of billionaire oligarchs have become major targets for Western sanctions over the war on Ukraine.

Last week, Canada announced it was freezing assets and banning business from Russian figures including Roman Abramovich, who has been ordered to sell his Chelsea Football Club in the United Kingdom. The U.K. and European Union have taken similar measures against Abramovich and others, and the U.S. has convened a multilateral task force dedicated to sanctioning these elites.

But while oligarchs traditionally wield outsized political influence in Russia, President Vladimir Putin has consolidated power over his decades in leadership. Questions remain about whether Russian billionaires — however incensed by the limits placed on their Western-style lives of excess — can pressure Russian President Vladimir Putin to end the war.

Today, Forbes’ John Hyatt uses his experience on the billionaire beat to explain where the oligarchs’ wealth comes from, and what Western pressure on their wallets could mean for Putin.