Toshiba Corp President and CEO Satoshi Tsunakawa attends a news conference at the company's headquarters in Tokyo, Japan, December 27, 2016. Photo: Reuters/Toru Hanai

Toshiba Corp shares slumped on Thursday after Nikkei business news said the company faces a loss of more than 500 billion yen ($4.36 billion) at its nuclear reactor business in the US.

Toshiba said in a press release through the Tokyo Stock Exchange that it had not announced the reactor business loss, reported by the Nikkei business daily, or a separate report by public broadcaster NHK that it will sell other business units and assets to raise 300 billion yen.

Toshiba’s shares fell as much as 9.5 percent to 261 yen in Tokyo after trading was initially suspended. That compares with a 0.9 percent gain in the benchmark Nikkei 225 index.