Five Diversified Telecommunication Services stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

This week, Maxcom Telecomunicaciones (NYSE:MXT) is showing significant improvement as the company’s rating hops from a C (“hold”) to a B (“buy”). Maxcom Telecomunicaciones offers local and long distance telephone services to residences and small to medium-sized businesses, as well as conference calling, data transmission, and high-speed Internet access. For more information, get Portfolio Grader’s complete analysis of MXT stock.

This week, Cogent Communications’ (NASDAQ:CCOI) ratings are up from a C last week to a B. Cogent Communications is a facilities-based provider of low-cost, high-speed Internet access and Internet Protocol (IP) communications services. For more information, get Portfolio Grader’s complete analysis of CCOI stock.

Hawaiian Telcom (NASDAQ:HCOM) boosts its rating from a C to a B this week. Hawaiian Telcom Holdco is a full-service provider of communications services, products and solutions in Hawaii. For more information, get Portfolio Grader’s complete analysis of HCOM stock.

The rating of KT Corp. (NYSE:KT) moves up this week, rising from a C to a B. KT provides telecommunication services including local, long distance, and international calling, satellite communication, data transmission, and wireless telephone services in South Korea. The stock price has risen 9.3% over the past month, better than the 3.2% decrease the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of KT stock.

Tata Communications’ (NYSE:TCL) ratings are looking better this week, moving up to a B from last week’s C. Tata Communications provides international telephone, telex and telegraphy services, international maritime mobile communications, INTELSAT business service and bureau fax and t-fax services. For more information, get Portfolio Grader’s complete analysis of TCL 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.