The Asian Development Bank (ADB) plans to increase its capital up to threefold from the current 5 trillion yen. The capital increase is aimed at strengthening its assistance to developing countries amid the deepening global financial crisis, informed sources said. Member countries agree on the need for an urgent capital boost for the Manila-based ADB, according to an official at the finance ministry in Japan, one of the bank's top contributors. It would be the bank's first capital boost in 15 years and the largest since it was set up. The fresh capital would come from the ADB's shareholder nations. Japan and the US are the biggest contributors with shares of 15.6 percent each in the bank.