Nikkei tumbles to lowest since October 2014 as bank concerns intensify

Japan's Nikkei share average closed at its lowest level since October 2014 on Wednesday as worries about the health of global banks and economic growth intensified. After a tumultuous start to the week, markets looked to Federal Reserve Chair Janet Yellen's congressional testimony later in the session for fresh cues on the policy outlook, which may provide some relief for markets. Mitsubishi UFJ Financial Group dived 7.1 percent, Sumitomo Mitsui Financial Group tumbled 4.0 percent and Mizuho Fin