TheTradeNews.com reports that a trade input error caused an inflated sell order to be posted on Nasdaq OMX Stockholm, leading to ABN AMRO being fined this week.
The sponsored access client put in a negative value of -5,000 shares in the volume field for a sell order, which its own trading system erroneously converted to more than 294 million shares. This order, for shares in Swedish manufacturer SKF, was sent to the market despite constituting around 70% of outstanding SKF shares and resulted in the execution of 800,000 shares.
It’s amazing that this was a manually entered trade, yet didn’t have sufficient data validation, let alone pre-trade controls.