A Mizuho Securities stock trader accidentally traded inputs, attempting to sell 610,000 shares of J-com stock at 1 Yen per share rather than one share of J-com stock at 610,000 Yen per share.
"Everyone in the market instantly knew the order was a mistake so some clever guys predicted that Mizuho Securities would have to put in a massive buy order later," said Hideo Mizutani, chief market analyst at Sieg Securities.
The estimated loss to Mizuho is over $200 million, as they had to buy back shares at something approximating their actual price.