Putin made a promise to protect a bank that is partly owned by a longtime ally, despite being blacklisted by Washington. Russia's response to the financial and visa restrictions imposed by the US was to create its own blacklist. Despite allies laughing off the sanctions, the Moscow stock exchange experienced a significant drop in shares, losing $70 billion in value in one month. President Obama also threatened to target major sectors of the Russian economy if they expanded into areas of Ukraine beyond Crimea. The US was doubtful of Russia's claims that troop movements near Ukraine were just military exercises, leading the OSCE to send monitors to Ukraine. Visa and MasterCard stopped processing payments for a Russian bank owned by individuals on the US blacklist, causing Russia to consider canceling foreign borrowing for 2014. In response to the crisis, the European Union imposed sanctions on several Russian officials and expressed a desire to reduce reliance on Russian energy. Putin signed a law ratifying the treaty making Crimea part of Russia and creating two new administrative districts. The annexation of Crimea was met with fireworks and celebrations by Russians in Simferopol, while Ukrainian and Tatar residents remained cautious and closed their doors. A recent referendum in Crimea, where Russian troops had taken control, overwhelmingly supported union with Russia, but was criticized by the US and EU as fraudulent. This paved the way for annexation in a short period of time. Obama's decision to target the finances of individuals close to Putin has escalated the diplomatic tensions. Putin defended Bank Rossiya, which was labeled by the US as the personal bank of senior Russian officials, stating it had no involvement in the events in Crimea. The bank, based in St Petersburg and partly owned by Putin's associate Yuri Kovalchuk, mainly serves clients in Russia's energy sector. Putin, asserting Crimea's right to self-determination, pledged to transfer his wages to Bank Rossiya. Other individuals on the US blacklist include oil trader Gennady Timchenko, the Rotenberg brothers, Putin's chief of staff, and others. Additionally, European leaders agreed to enhance their energy security measures after discussions on Friday. Despite progress in diversifying energy sources, Russia still supplies a significant portion of the EU's oil and gas, with a large amount passing through Ukraine. EU countries plan to negotiate joint supply deals with Moscow to strengthen their bargaining power. Van Rompuy stated the importance of moving towards an energy union. Merkel suggested US shale gas as an option for European countries seeking diversification. Obama is expected to discuss this issue at a summit with EU leaders. US credit card companies Visa and MasterCard stopped services for payment transactions with Russia's SMP bank, leading to concerns about the secondary ripple effects of sanctions. French banker in Moscow called the announced measures cosmetic and highlighted the risk to transfers in US dollars for the Russian economy. Obama mentioned potential sanctions against various economic sectors if Russia makes military moves into eastern and southern Ukraine. Ukrainian troops in Crimea, surrounded by Russian forces, continued to leave their bases. German Foreign Minister Frank-Walter Steinmeier expressed concern about the unstable and threatening situation in Ukraine, urging OSCE observers to begin their work promptly. European governments, including Germany and France, took actions against Russia, such as suspending defence-related exports and military cooperation. In Brussels, EU leaders showed their support for Ukraine's new leadership by signing a political agreement with Prime Minister Arseniy Yatseniuk and promising financial aid once a deal with the IMF is reached. The IMF is in advanced talks with Ukraine for a loan programme tied to economic reforms. Market reactions to the situation included a drop in Russia's stock index and credit rating agencies changing their outlook on Russia to negative. Russian Prime Minister Dmitry Medvedev announced plans to increase financial pressure on Ukraine by demanding repayment of $11 billion under a gas supply contract.