This week, four chemicals stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

Platform Specialty Products Corp. (PAH) is making progress this week as its rating of C (“hold”) from last week increases to a B (“buy”) rating this week. In Portfolio Grader’s specific subcategory of Earnings Surprise, PAH also gets an A. For more information, get Portfolio Grader’s complete analysis of PAH stock.

Burcon NutraScience Corporation (BUR) earns a B this week, jumping up from last week’s grade of C. Burcon NutraScience specializes in nutrition, health and wellness in the field of functional and renewable plant proteins. For more information, get Portfolio Grader’s complete analysis of BUR stock.

This is a strong week for Valspar Corporation (VAL). The company’s rating climbs to B from the previous week’s C. Valspar is a coating and paint manufacturer and distributor. For more information, get Portfolio Grader’s complete analysis of VAL stock.

This week, Potash Corporation of Saskatchewan Inc. (POT) pushes up from a C to a B rating. Potash Corporation of Saskatchewan produces potash, phosphate, and nitrogen to the agricultural and industrial industries worldwide. For more information, get Portfolio Grader’s complete analysis of POT 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.