Investment bank UBS blamed a system error for a blunder which ledit to place an order on the Tokyo Stock Exchange for £21bn instead of £210,000.
"Asystem error occurred in placing a cross-trade order in the Tokyo Stock Exchange's ToSTNeT system. The cross-trade order for Capcom Co.'s convertible bond series 5 was sent for ¥3trillioninstead of ¥30m," said UBS.
The Tokyo exchange suspended trading in the affected issue and the trade was subsequently cancelled at no cost to UBS.
Bob McDowall, analyst at Towergroup, said this type of error has happened in the past and firms have even lost money.
"I am surprised the exchanges have not introduced safeguards in the form of prompts when trades overa certain sizeare made," he added.
Exchanges could introduce automated safeguards to prevent similarmistakes, whichcouldpotentially affect the wider market.