There is a puzzling mismatch in market sentiment among longs and shorts, with both increasing their positions. The two most widely shorted exchange-traded funds are the SPDR S&P 500 ETF and the iShares Russell 2000 with $55.9 billion in shorts and $13.5 billion, respectively. According to Ihor Dusaniwsky, head of research at S3 Partners, the mismatch could be the result of pre-election market volatility, Fed Funds rate increase uncertainty, or volatility in the price of crude oil. Read the original story from Barron's.