This article tries to absolve short selling of responsibility for the bank values crash a couple of weeks ago (it does look like institutions dumped their bank stock as soon as they found out that short-selling was being re-enabled).
But the interesting statistic in this article is that over 3 percent of Barclays shock was out on loan, even while short-selling was banned. Which begs a question:
Why would people or institutions want to borrow stock, if they are not using them to sell short?