The ratings of 3 Commercial Services & Supplies stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This is a rough week for UniFirst Corporation (UNF). The company’s rating falls to D from the previous week’s C. UniFirst Corporation provides workplace uniforms and protective clothing, including shirts, pants, jackets, coveralls, lab coats, smocks and aprons and specialized protective wear, such as flame resistant and high visibility garments. For more information, get Portfolio Grader’s complete analysis of UNF stock.

Mobile Mini, Inc. (MINI) slips from a C to a D this week. Mobile Mini, Inc. provides portable storage solutions in North America and the United Kingdom. The company also gets F’s in operating margin growth. For more information, get Portfolio Grader’s complete analysis of MINI stock.

Fuel Tech, Inc. (FTEK) declines this week from a D to a F. Fuel Tech, Inc. develops and commercializes air pollution control technologies and provides engineering services. The company also gets F’s in earnings growth, earnings surprise, and free cash flow. For more information, get Portfolio Grader’s complete analysis of FTEK 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.