Four chemicals stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

This week, Platform Specialty Products Corp. (PAH) is showing significant improvement as the company’s rating hops from a C (“hold”) to a B (“buy”). In Portfolio Grader’s specific subcategory of Earnings Surprise, PAH also gets an A. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of PAH stock.

This week, Valspar Corporation (VAL) pushes up from a C to a B rating. Valspar is a coating and paint manufacturer and distributor. Shares of the stock have been changing hands at an unusually rapid pace, up 689.8% from the week prior. For more information, get Portfolio Grader’s complete analysis of VAL stock.

This week, ForceField Energy Inc. (FNRG) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. For more information, get Portfolio Grader’s complete analysis of FNRG stock.

Potash Corporation of Saskatchewan Inc. (POT) is seeing ratings go up from a C last week to a B this week. Potash Corporation of Saskatchewan produces potash, phosphate, and nitrogen to the agricultural and industrial industries worldwide. Shares of the stock have been trading at an exceptionally rapid pace, up 936.6% from the week prior. 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.