SPDR S&P Biotech ETF (NYSEArca: XBI)
October returns: -6.8%
Comment: Biotech stocks began to falter during the height of the U.S. debt default scare. Investors became wary about the potential ramifications of slower FDA approval cycle and steep valuations after an incredible year. Unlike other biotech ETFs, XBI equally weights its holdings and has deeper exposure to small-cap names.