Short sellers continue to bet on biotech firms compared to the July 31 settlement date. Arena...

|About: Arena Pharmaceuticals, Inc. (ARNA)|By:, SA News Editor

Short sellers continue to bet on biotech firms compared to the July 31 settlement date. Arena Pharmaceuticals (ARNA -0.3%), Gilead Sciences (GILD +1.4%), Pharmacyclics (PCYC -2.2%), Vertex Pharmaceuticals (VRTX -0.6%) and VIVUS (VVUS -0.4%) all saw short interest rise more than 9% between July 31 and August 15. Two exceptions to the rule worth noting however, are Alexion Pharmaceuticals (ALXN +0.1%) and Biogen Idec (BIIB -0.4%), both of which saw short interest decline by 10% and 8.4%, respectively.