The grades of four commercial services stocks are better this week, according to the Portfolio Grader database. Every one of these stocks has an “A” (“strong buy”) or “B” overall (“buy”) rating.

This week, Republic Services, Inc. (RSG) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Republic Services provides non-hazardous solid waste collection services for commercial, industrial, municipal and residential customers. In Portfolio Grader’s specific subcategory of Margin Growth, RSG also gets an A. For more information, get Portfolio Grader’s complete analysis of RSG stock.

Viad Corp (VVI) is bettering its rating of C (“hold”) from last week to a B (“buy”) this week. Viad provides high-quality, place-based marketing services in North America, the United Kingdom and the United Arab Emirates, as well as travel and recreation services in the United States and Canada. For more information, get Portfolio Grader’s complete analysis of VVI stock.

Hudson Technologies, Inc.’s (HDSN) ratings are looking better this week, moving up to a B from last week’s C. Hudson Technologies sells refrigerants, as well as provides a variety of related services. For more information, get Portfolio Grader’s complete analysis of HDSN stock.

Waste Management, Inc. (WM) gets a higher grade this week, advancing from a B last week to an A. Waste Management provides collection, transfer, recycling, disposal and waste-to-energy services. For more information, get Portfolio Grader’s complete analysis of WM 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.