For the first time, private equity firms must contend with economic penalties against a major economy after the US and European Union issued extensive sanctions against Russia. Although US and European firms say they so far have seen little direct effect, the sanctions are complex and their impact could be wide.

In August, EIG Global Energy Partners ordered a kind of internal review it had never done before. The one-week review, involving EIG's own legal team and the lawyers for its portfolio companies, scrutinised its companies' business partners: vendors, suppliers, customers, co-investors and joint-venture partners. The goal was to determine whether any of the parties would be subject to the sanctions applied to Russia for its support of Ukrainian separatists.