Short interest on the Nasdaq dipped 1.2 percent in early August, the exchange said on Friday, suggesting a decrease in bearish sentiment in the stock market. As of August 15, short interest declined to about 7.609 billion shares, compared with 7.700 billion s hares as of July 31. Investors who sell securities 'short' borrow shares and then sell them, expecting the stock to fall so they can buy the shares back at the lower price, return them to the lender and pocket the difference.