This week, the overall grades of 3 Diversified Telecommunication Services stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

TELUS Corporation (TU) slips from a D to a F this week. TELUS Corporation is a telecommunications company that offers products and services in Canada. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of TU stock.

Telefonica SA Sponsored ADR (TEF) earns a D this week, moving down from last week’s grade of C. Telefonica SA Sponsored ADR is a telecommunications group that provides services through its telecommunications networks. For more information, get Portfolio Grader’s complete analysis of TEF stock.

Slipping from a D to a F rating, Windstream Holdings, Inc. (WIN) takes a hit this week. Windstream Holdings, Inc. is a company that provides communications and technology solutions, including high-speed Internet access, digital television services, and voice services. The company also gets F’s in operating margin growth, earnings growth, earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of WIN 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.