The grades of three chemicals stocks are better this week, according to the Portfolio Grader database. Every one of these stocks has an “A” (“strong buy”) or “B” overall (“buy”) rating.

KMG Chemicals, Inc. (KMG) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. KMG Chemicals is engaged in the manufacture, formulation, and distribution of specialty chemicals primarily in the United States, Canada, Mexico, Europe, and Asia. In Portfolio Grader’s specific subcategory of Earnings Momentum, KMG also gets an A. For more information, get Portfolio Grader’s complete analysis of KMG stock.

CF Industries Holdings, Inc. (CF) earns a B this week, jumping up from last week’s grade of C. CF Industries manufacturers and distributes nitrogen and phosphate fertilizer products in North America. The current dividend yield is 6%. For more information, get Portfolio Grader’s complete analysis of CF stock.

Balchem Corporation (BCPC) is seeing ratings go up from a C last week to a B this week. Balchem develops, manufactures, and markets of specialty ingredients and products for the food, nutritional, feed, pharmaceutical, and medical sterilization industries. For more information, get Portfolio Grader’s complete analysis of BCPC 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.