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

Sears Hometown & Outlet Stores, Inc.. The company also gets F’s in operating margin growth. For more information, get Portfolio Grader’s complete analysis of SHOS stock.

Gastar Exploration, Inc. (GST) is a natural gas exploration company. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings revisions, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of GST stock.

Chesapeake Energy Corporation (CHK) explores, develops and acquires properties for the production of natural gas and crude oil from underground reservoirs. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings revisions, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of CHK stock.

Advanced Micro Devices, Inc.. The company also gets F’s in sales growth, operating margin growth, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of AMD stock.

Maxwell Technologies, Inc. (MXWL) develops, manufactures and markets products and services for purification and information technologies and power-conversion systems and components. The company also gets F’s in sales growth, operating margin growth, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of MXWL 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.