Toshiba Corp. plunged by the most on record as the once heralded U.S. nuclear renaissance turns into a nightmare for the Japanese company. The shares fell by 20 percent, the most since 1974, according to available data, to close at 312 yen in Tokyo, following a 12 percent drop Tuesday.

Toshiba Corp. plunged by the daily limit in Tokyo as the once heralded U.S. nuclear renaissance is turning into a nightmare for the Japanese company. The shares fell by 20 percent to 311.6 yen in Tokyo, following a 12 percent drop Tuesday.