The hedge fund founded and, until recently, run by billionaire environmentalist Tom Steyer was involved in a deal to sell a stake in a Russian oil company to a Russian oligarch who is the target of U.S. sanctions. Farallon Capital Management sold a part of its stake in Russian firm Geotech Oil Services to the Volga Group, a Luxembourg-based investment firm owned by Russian billionaire Gennady Timchenko, in 2010. Four years later, in April 2014, the U.S. Treasury Department announced that it would target Timchenko, Volga, and a number of companies associated with them, in a round of sanctions aimed...