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”).

This week, Ashland Global Holdings, Inc.’s (ASH) rating worsens to a D from the company’s C rating a week ago. Ashland Global Holdings, 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 earnings momentum. For more information, get Portfolio Grader’s complete analysis of ASH stock.

This week, BioAmber, Inc. (BIOA) drops from a C to a D rating. The company also gets F’s in earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of BIOA stock.

AgroFresh Solutions, Inc.’s (AGFS) rating weakens this week, dropping to a F versus last week’s D. The company also gets F’s in operating margin growth, earnings surprise, and free cash flow. For more information, get Portfolio Grader’s complete analysis of AGFS stock.

Slipping from a C to a D rating, Tantech Holdings Ltd. (TANH) takes a hit this week. The company also gets F’s in sales growth and earnings growth. For more information, get Portfolio Grader’s complete analysis of TANH stock.

TerraVia Holdings, Inc. (TVIA) is having a tough week. The company’s rating falls from a D to a F. The company also gets F’s in sales growth and free cash flow. For more information, get Portfolio Grader’s complete analysis of TVIA 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.