Toshiba chairman steps down as company takes $6.3B hit from nuclear unit

After a day of delays and confusion, Japan's Toshiba Corp said on Tuesday it would book a $6.3 billion hit to its U.S. nuclear unit, a write-down that wipes out its shareholder equity and leaves the loss-making group scrambling for capital. The company also said on Tuesday that its chairman, Shigenori Shiga, would resign, ending weeks of speculation. Hours earlier on Tuesday, the battered conglomerate rattled investors by failing to release its earnings on schedule, saying initially it was 'not ready' and then announcing later it needed more time to probe its Westinghouse nuclear business after internal reports uncovered potential problems.