This week, the overall grades of 4 Commercial Services & Supplies stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Slipping from a D to a F rating, Pitney Bowes Inc. (PBI) takes a hit this week. Pitney Bowes Inc. sells and finances, rents, and services integrated mail and document management systems. For more information, get Portfolio Grader’s complete analysis of PBI stock.

This is a rough week for Covanta Holding Corporation (CVA). The company’s rating falls to D from the previous week’s C. Covanta Holding Corporation develops, owns, and operates infrastructure for the conversion of waste to energy, as well as other waste disposal and renewable energy production businesses in the Americas, Europe, and Asia. The company also gets F’s in earnings momentum and free cash flow. For more information, get Portfolio Grader’s complete analysis of CVA stock.

Atento SA (ATTO) declines this week from a D to a F. The company also gets F’s in operating margin growth, earnings growth, earnings revisions, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of ATTO stock.

Perma-Fix Environmental Services, Inc. (PESI) earns a D this week, moving down from last week’s grade of C. Perma-Fix Environmental Services, Inc. provides industrial and nuclear-waste management services, and Consulting Engineering Services. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings momentum, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of PESI 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.