This week, 4 Food & Staples Retailing stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

This week, Casey’s General Stores, Inc. (CASY) pushes up from a C to a B rating. Casey’s General Stores, Inc. operate convenience stores in the midwestern United States. The company also gets A’s in operating margin growth and return on equity. For more information, get Portfolio Grader’s complete analysis of CASY stock.

Wal-Mart Stores, Inc.’s (WMT) ratings are looking better this week, moving up to a A from last week’s B. Wal-Mart Stores, Inc. operates Walmart discount stores, supercenters, Neighborhood Markets and Sam’s Club locations in the United States. The company also gets A’s in return on equity. For more information, get Portfolio Grader’s complete analysis of WMT stock.

Weis Markets, Inc. (WMK) shows solid improvement this week. The company’s rating rises from a B to a A. Weis Markets, Inc. is engaged in the retail sale of food in Pennsylvania and surrounding states. For more information, get Portfolio Grader’s complete analysis of WMK stock.

This is a strong week for Companhia Brasileira de Distribuicao Sponsored ADR Pfd Class A (CBD). The company’s rating climbs to B from the previous week’s C. Companhia Brasileira de Distribuicao Sponsored ADR Pfd Class A is a food retailer in Brazil. For more information, get Portfolio Grader’s complete analysis of CBD 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.