Watch Out For These 4 Short-Interest Gainers In Monday's Trading

The Dow was up nearly 100 points Monday as it adds to the gains of the last couple of trading days. Here are four of the day's biggest gainers with high short interest.

VirnetX Holding Corporation VHC

VirnetX continued to rise Monday despite the highest short interest among Monday's top gainers, amounting to 30.7 percent of its float as of November 28. The Internet security software company recently settled a lawsuit against Microsoft. The tech giant paid VirnetX $23 million to settle a patent and license dispute. The stock recently traded at $6.06, down 3.4 percent.

Image Sensing Systems, Inc. ISNS

The developer of video and radar image processing products for use in traffic, security, police and parking applications has exhibited a significant short interest of 20.5 percent as of late November. The stock was up more than 8 percent Monday.

Achillion Pharmaceuticals, Inc. ACHN

The biopharmaceutical company engaged in the development of antivirals for treatment of infectious diseases had a short interest of 24.7 percent of its float as of November 28. The stock achieved a new 52-week high on Monday ($16.74) and saw an unusually large activity in terms of volume.

ZaZa Energy Corporation ZAZA

The last company on the list has been engaged in the development and exploration of unconventional oil and gas assets in the United States. It has a short interest equal to 17.9 percent of the company's float as of the end of last month. The company's stock showed gains during the last five trading days, and those gains jumped another 20 percent at $2.05 in Monday's trading.