This week, four commercial services stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

This week, Republic Services, Inc. (RSG) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. 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’s (VVI) grade is moving up to a B (“buy”) this week from last week’s C (“hold”). 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. Shares of the stock have been trading at an exceptionally rapid pace, up 406.9% from the week prior. For more information, get Portfolio Grader’s complete analysis of VVI stock.

Hudson Technologies, Inc. (HDSN) boosts its rating from a C to a B this week. 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) is seeing ratings go up from a B last week to an A this week. 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.