This week, these five stocks have the worst ratings in Operating Margin Growth, one of the eight Fundamental Categories on Portfolio Grader.

Aeroflex (NYSE:ARX) engages in the design, engineering, manufacture, and sale of microelectronic products, and test and measurement equipment. ARX also gets F’s in Earnings Growth, Earnings Surprises, Equity, and Sales Growth. Shares of the stock have declined 43.6% since January 1. This is worse than the S&P 500, which has seen a 11.2% increase over the same period. For more information, get Portfolio Grader’s complete analysis of ARX stock.

AVEO (NASDAQ:AVEO) engages in discovering, developing, and commercializing targeted cancer therapies using its Human Response Platform. AVEO gets F’s in Earnings Growth, Earnings Momentum, Equity, Cash Flow, and Sales Growth as well. Shares of the stock have declined 49.7% since January 1. For more information, get Portfolio Grader’s complete analysis of AVEO stock.

Investment Technology Group (NYSE:ITG) is an agency brokerage and financial technology firm that partners with asset managers globally to provide innovative solutions spanning the investment continuum. ITG also gets F’s in Earnings Momentum, Analyst Earnings Revisions, Earnings Surprises, Cash Flow, and Sales Growth. Since January 1, ITG has fallen 26.8%. For more information, get Portfolio Grader’s complete analysis of ITG stock.

Suntech Power Holdings (NYSE:STP) is a solar energy company that designs, develops, manufactures and markets PV cells and molecules. STP gets F’s in Earnings Growth, Earnings Momentum, Analyst Earnings Revisions, Equity, Cash Flow, and Sales Growth as well. Shares of the stock have declined 52% since January 1. For more information, get Portfolio Grader’s complete analysis of STP stock.

Boston Scientific (NYSE:BSX) is a developer, manufacturer and marketer of medical devices that are used in a range of interventional medical specialties. BSX gets F’s in Earnings Growth, Earnings Momentum, Cash Flow, and Sales Growth as well. For more information, get Portfolio Grader’s complete analysis of BSX stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.