This week, three Packaging stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Rock-Tenn Co. (NYSE:RKT) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. Rock-Tenn manufactures packaging, including folding cartons, as well as recycled paperboard, and specialty corrugated packaging and display products. In Portfolio Grader’s specific subcategories of Earnings Momentum and Sales Growth, RKT also gets A’s. For more information, get Portfolio Grader’s complete analysis of RKT stock.

This week, Packaging Corp. of America (NYSE:PKG) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Packaging Corporation of America manufactures containerboard and corrugated packaging products for use in protecting goods during shipment. The stock price has risen 11.5% over the past month, better than the 4% increase the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of PKG stock.

This week, Boise‘s (NYSE:BZ) ratings are up from a C last week to a B. Boise engages in the manufacture and sale of packaging and paper products in the United States, Europe, Mexico, and Canada. Wall Street has pushed the stock higher by 16.5% over the past month. For more information, get Portfolio Grader’s complete analysis of BZ 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.