Yesterday, the Hong Kong stock exchange suspended trading on seven companies who were the victims of hacks. The attack took place on a page of the exchange's site where companies make announcements so the reasoning was that hackers could have potentially made companies say whatever they wanted, thus affecting all kinds of stocks. The seven companies that were about to make announcements had trading of their shares halted for half the day.

This has been happening more and more often, including this week when hackers commandeered the public facing blog of BlackBerry. What does it mean to stocks, what does it mean to companies, when their official communications can be commandeered, when they're no longer in charge of their own communications? Sometimes it happens in grandiose ways, but it could just as easily happen in more subtle and undetectable ways.

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