This week, 4 Chemicals stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

A. Schulman, Inc. (SHLM) slips from a D to a F this week. A. Schulman, Inc. sells plastic resins and compounds, which are used as raw materials by its customers. The company also gets F’s in earnings surprise. For more information, get Portfolio Grader’s complete analysis of SHLM stock.

Slipping from a D to a F rating, OCI Partners LP (OCIP) takes a hit this week. The company also gets F’s in earnings revisions and free cash flow. For more information, get Portfolio Grader’s complete analysis of OCIP stock.

Kronos Worldwide, Inc. (KRO) experiences a ratings drop this week, going from last week’s D to a F. Kronos Worldwide, Inc. produces titanium dioxide pigments. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings revisions, earnings momentum, and free cash flow. For more information, get Portfolio Grader’s complete analysis of KRO stock.

OMNOVA Solutions Inc. (OMN) declines this week from a D to a F. OMNOVA Solutions Inc. develops, manufactures, and markets emulsion polymers, specialty chemicals, and decorative and building products for industrial, commercial, and consumer markets. The company also gets F’s in sales growth, operating margin growth, and earnings growth. For more information, get Portfolio Grader’s complete analysis of OMN 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.