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

Suntech Power Holdings Co. Ltd. Sponsored ADR (STP) is a solar energy company that designs, develops, manufactures and markets PV cells and molecules. STP also gets F’s in Earnings Growth, Equity, Operating Margin Growth and Sales Growth. For more information, get Portfolio Grader’s complete analysis of STP stock.

ATP Oil & Gas (ATPG) is engaged in the acquisition, development and production of oil and natural gas properties in the Gulf of Mexico and the U.K. ATPG also gets F’s in Analyst Earnings Revisions and Sales Growth. For more information, get Portfolio Grader’s complete analysis of ATPG stock.

NII Holdings, Inc. Class B (NIHD) provides mobile communications for business customers in Latin America. NIHD gets F’s in Earnings Momentum, Analyst Earnings Revisions, Equity and Sales Growth as well. For more information, get Portfolio Grader’s complete analysis of NIHD stock.

Tower Group International Ltd. (TWGP) is a provider of property and casualty insurance products and services. TWGP also gets F’s in Earnings Momentum, Analyst Earnings Revisions, Equity, Operating Margin Growth and Sales Growth. For more information, get Portfolio Grader’s complete analysis of TWGP stock.

A123 Systems (AONE) designs, develops, manufactures, and sells rechargeable lithium-ion batteries and energy storage systems worldwide. AONE gets F’s in Analyst Earnings Revisions, Equity and Sales Growth as well. For more information, get Portfolio Grader’s complete analysis of AONE 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.