Toshiba admits to a ruinous overpayment for an American nuclear firmIts share price plunged by 40% in three days as investors worried about its financial viability THE probe in 2015 into one of Japan’s largest-ever accounting scandals, at Toshiba, an electronics and nuclear-power conglomerate that has been the epitome of the country’s engineering prowess, concluded that number-fiddling at the firm