The Moscow Stock Exchange resumed trading of some shares Thursday, the second stage in a phased re-opening after being suspended for a month due to Russia's military operation in Ukraine. Trading renewed for only 33 of the largest companies that make up the ruble-denominated MOEX Russia Index, which saw gains of 10% at opening but closed at 4.4%. The RTS Index, which is calculated in U.S. dollars, was down 9.0% as markets closed. The companies trading on Thursday include Russian energy giants Gazprom and Rosneft, and the country's largest banks Sberbank and VTB, which are under U.S. sanctions. Other companies trading on the market included metals giants Nornickel and Rusal, several private companies and Russia's flag-carrier airline Aeroflot. The Moscow exchange suspended trading hours after President Vladimir Putin sent thousands of troops into pro-Western Ukraine on Feb. 24.