<i>The losses on a bad trade can easily outstrip that wrist-slap</i><p>$340 million (eventually reduced to a bit north of $200 million) in one incident at Mizuho Securities in Japan back in 2006.<p>Word to the wise: There is a big difference between selling one share at 610,000 yen ($6000) and selling 610,000 shares at one yen.<p>Word to the wise, part #2: Nobody at the Tokyo Stock Exchange feels that they have the authority to cancel an order from Mizuho, even if Mizuho tries to sell a multiple of the market cap of a company in a single transaction.  (This got regulators mighty pissed off, incidentally.)