The ratings of three diversified telecommunication services stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, Premiere Global Services, Inc. (PGI) falls to a D (“sell”), worse than last week’s grade of C (“hold”). Premiere Global Services is a global provider of conferencing and collaboration services. For Portfolio Grader’s specific subcategory of Earnings Momentum, PGI also gets an F. The stock has a trailing PE Ratio of 38.30. For more information, get Portfolio Grader’s complete analysis of PGI stock.

The rating of inContact, Inc. (SAAS) slips from a C to a D. inContact provides cloud-based contact center software services and network connectivity in the United States. The stock gets F’s in Earnings Revisions and Equity. For a full analysis of SAAS stock, visit Portfolio Grader.

KT Corporation Sponsored ADR (KT) ratings are on the decline this week as the company earns an F (“strong sell”). Last week, it received a D (“sell”). KT provides telecommunication services including local, long distance, and international calling, satellite communication, data transmission, and wireless telephone services in South Korea. The stock gets F’s in Earnings Growth, Earnings Momentum, Earnings Revisions and Margin Growth. To get an in-depth look at KT, get Portfolio Grader’s complete analysis of KT 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.