[andylei]

>> This is most likely the catalyst for why UBS is actually suing

unlikely. from their quarterly report " NASDAQ ultimately filled all of these orders, exposing UBS to far more shares than our clients had ordered".

their clients ordered X shares of FB. UBS sent out 5 * X shares (or something like that). they sent out extra orders because NASDAQ wasn't sending acknowledgements for the initial orders. so UBS had to liquidate 4 * X shares at a loss, because the price took a dive. the loss from liquidation is why they sued.