The grades of 4 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.

Sherwin-Williams Company (SHW) boosts its rating from a C to a B this week. Sherwin-Williams Company manufactures, distributes, and sells paint, coatings and related products to professional, industrial, commercial, and retail customers. The company also gets A’s in return on equity. For more information, get Portfolio Grader’s complete analysis of SHW stock.

Ecolab Inc. (ECL) shows solid improvement this week. The company’s rating rises from a C to a B. Ecolab Inc. develops and markets products and services for the hospitality, foodservice, healthcare, and industrial markets primarily in the United States. The company also gets A’s in return on equity. For more information, get Portfolio Grader’s complete analysis of ECL stock.

This week, Chemtura Corporation (CHMT) pushes up from a B to a A rating. Chemtura Corporation manufactures and markets a number of polymer and specialty chemical products. The company also gets A’s in operating margin growth, earnings growth, earnings revisions, earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of CHMT stock.

KMG Chemicals, Inc. (KMG) improves from a C to a B rating this week. KMG Chemicals, Inc. is engaged in the manufacture, formulation, and distribution of specialty chemicals primarily in the United States, Canada, Mexico, Europe, and Asia. The company also gets A’s in operating margin growth and earnings growth. For more information, get Portfolio Grader’s complete analysis of KMG 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.