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

Ashland Inc. (ASH) experiences a ratings drop this week, going from last week’s C to a D. Ashland Inc. is a global specialty chemicals company and provider of products, services, and solutions for a variety of industries. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of ASH stock.

This is a rough week for LyondellBasell Industries NV (LYB). The company’s rating falls to D from the previous week’s C. LyondellBasell Industries NV produces chemicals, fuels, and polymers used for packaging, clean fuels, durable textiles, medical applications, construction materials, and automotive parts. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of LYB stock.

Tredegar Corporation (TG) is having a tough week. The company’s rating falls from a C to a D. Tredegar Corporation manufactures plastic films, elastics and laminate materials, mainly for personal and household care products and packaging and surface protection applications. The company also gets F’s in operating margin growth, earnings growth, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of TG stock.

AgroFresh Solutions, Inc. (AGFS) earns a F this week, moving down from last week’s grade of D. 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 AGFS 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.