Japan's benchmark Nikkei 225 index tumbles 12.4% in its worst single-day loss since 'Black Monday' of 1987

Japan's benchmark Nikkei 225 index tumbles 12.4% in its worst single-day loss since 'Black Monday' of 1987

TOKYO -- Japan's benchmark Nikkei 225 index tumbles 12.4% in its worst single-day loss since 'Black Monday' of 1987.