A trader at a small Japanese stock brokerage bungled the market debut of Web advertiser Adways last night when he typed the wrong trading code and mistakenly sold $18.7 million worth of shares in the firm.
Japanese stock markets have been hit by a series of trading errors in recent months. In the most serious, a trader at Mizuho Securities mistakenly offered 610,000 shares at 1 yen each last December instead of the intended one share at 610,000 yen.
The mistake cost the brokerage about $335 million.
Adways' stock first traded at 1.47 million yen ($12,730) on the Tokyo Stock Exchange's Mothers market for startups, up 5 per cent from its IPO price of 1.40 million yen.
It had last changed hands at 1.43 million yen when the market closed, with a glut of bids waiting at its daily limit of 1.67 million yen.
Tachibana placed the errant sell order just after trading opened at 9am local time. It offered 2,600 shares at 1,670 yen each - a small fraction of Adways' debut price.
The Tachibana trader had intended to sell shares in CDG Co. Ltd., another stock that debuted on Tuesday, the brokerage said. CDG has a similar trading code to Adways', but its per-share price is much lower.
Adways unexpectedly benefited from the error, however, as investors bid the shares up by 19 per cent over their initial public offering (IPO) price on expectations that the broker, Tachibana Securities, would have to buy back the shares it sold.
The trader quickly cancelled the order, but not before 1,482 trades were settled, a number equivalent to just under 10 per cent of Adways' outstanding shares.
"It was an input error. The trader noticed the mistake immediately and cancelled, but it was too late to stop some of the shares from trading," Tachibana Vice President Takahiro Tsuchiya told a news conference.