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

Premiere Global Services, Inc.’s (PGI) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Premiere Global Services is a global provider of conferencing and collaboration services. PGI also rates an F in Portfolio Grader’s specific subcategory of Earnings Momentum. Shares of the stock have been trading at an exceptionally rapid pace, up fourfold from the week prior. The stock’s trailing PE Ratio is 35.50. To get an in-depth look at PGI, get Portfolio Grader’s complete analysis of PGI stock.

inContact, Inc. (SAAS) gets weaker ratings this week as last week’s C drops 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. The stock price has dropped 14.8% over the past month, worse than the 1.3% decrease the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of SAAS stock.

KT Corporation Sponsored ADR (KT) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). KT provides telecommunication services including local, long distance, and international calling, satellite communication, data transmission, and wireless telephone services in South Korea. In Earnings Growth, Earnings Momentum, Earnings Revisions and Margin Growth the stock gets F’s. 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.