As the S&P 500 continues to trade near record highs, short interest appears to be on the rise, again.
NYSE Euronext reports short interest rose more than 1.53 percent in November to 27.84 billion shares, its largest amount in five months.
Just in the last two weeks of November, more than 43 percent of S&P 500 stocks saw an average 10 percent increase in short interest.
This year has not been kind to short sellers, which have seen the S&P jump 24 percent, or its largest gain in a decade.
But some investors believe the tide may change. Hedge fund manager Bill Fleckenstein recently told CNBC he was restarting his short fund, while hedge fund titan Jim Chanos said he's finding many more opportunities on the short side.