Some of you may already know of this incidence, but I just read it for the first time and thought it might be of interest to others:

The “fat-fingered” Mizuho trader

A Mizuho Securities trader sold 610,000 shares in job recruiting company J-Com Co. for 1 yen apiece, instead of an intended sale of 1 share at 610,000 yen. Mizuho said it was unable to cancel the order, causing it to lose about $340 million. The mistake was attributed to the “fat-finger” syndrome, shorthand for gaffes made when traders hit the wrong button on a keyboard and lose a bundle.

The Tokyo stock exchange later acknowledged that a glitch in its system made it impossible to cancel the trade. Mizuho and the exchange have discussed sharing some of the losses, but have so far failed to reach an agreement.

Source: http://articles.moneycentral.msn.com...estLosers.aspx