TOKYO, March 13 : Mitsubishi UFJ Financial Group will closely monitor liquidity when issuing loans, an executive said, as Japanese banks prepare to potentially back projects under the country's $550 billion investment package in the United States. Japanese financial institutions are expected to participate in the initiative alongside support from state-owned agencies Japan Bank for International Cooperation (JBIC) and Nippon Export and Investment Insurance (NEXI), which are providing equity,