The ratings of 5 Chemicals stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

CF Industries Holdings, Inc. (CF) declines this week from a C to a D. CF Industries Holdings, Inc. manufacturers and distributes nitrogen and phosphate fertilizer products in North America. The company also gets F’s in earnings surprise and free cash flow. For more information, get Portfolio Grader’s complete analysis of CF stock.

A. Schulman, Inc. (SHLM) gets weaker ratings this week as last week’s C drops to a D. A. Schulman, Inc. sells plastic resins and compounds, which are used as raw materials by its customers. For more information, get Portfolio Grader’s complete analysis of SHLM stock.

Mosaic Company’s (MOS) rating weakens this week, dropping to a F versus last week’s D. Mosaic Company produces and distributes crop nutrients to the agricultural communities located in North America and other countries. For more information, get Portfolio Grader’s complete analysis of MOS stock.

This week, Sociedad Quimica Y Minera De Chile S.A. Sponsored ADR Pfd Class B (SQM) drops from a C to a D rating. Sociedad Quimica Y Minera De Chile S.A. Sponsored ADR Pfd Class B produces and distributes fertilizers, iodine, lithium and other industrial chemicals. The company also gets F’s in earnings surprise. For more information, get Portfolio Grader’s complete analysis of SQM stock.

Slipping from a C to a D rating, Orion Engineered Carbons SA (OEC) takes a hit this week. For more information, get Portfolio Grader’s complete analysis of OEC 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.