The overall ratings of three diversified telecommunication services stocks are down on Portfolio Grader this week. 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. In Portfolio Grader’s specific subcategory of Earnings Momentum, PGI also gets an F. The stock currently has a trailing PE Ratio of 28.20. For more information, get Portfolio Grader’s complete analysis of PGI stock.

The rating of inContact, Inc. (SAAS) declines this week 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. The stock price has fallen 6.6% over the past month, worse than the 1.3% decrease the Nasdaq has seen over the same period of time. For a full analysis of SAAS stock, visit Portfolio Grader.

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. The stock gets F’s in Earnings Growth, Earnings Momentum, Earnings Revisions and Margin Growth. At $13.74, the stock is below the 50-day moving average of $14.28. Shares of the stock have been trading at an exceptionally rapid pace, up twofold from the week prior. 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.