This week, three Diversified Telecommunication Services stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Alaska Communications Systems Group’s (NASDAQ:ALSK) grade is moving up to a B (“buy”) this week from last week’s C (“hold”). Alaska Communications Systems provides integrated communications services primarily in Alaska. In Portfolio Grader’s specific subcategories of Earnings Growth, Earnings Revisions, Earnings Surprise, Equity, and Cash Flow, ALSK also gets A’s. Shares of ALSK have increased 90.3% over the past month, better 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 ALSK stock.

Atlantic Tele-Network (NASDAQ:ATNI) boosts its rating from a C to a B this week. Atlantic Tele-Network is a provider of wireless and wireline telecommunications services in North America and the Caribbean. For more information, get Portfolio Grader’s complete analysis of ATNI stock.

Chunghwa Telecom (NYSE:CHT) earns a B this week, jumping up from last week’s grade of C. Chunghwa Telecom is a telecommunications service provider that offers fixed line services, cellular services, and Internet and data services in Taiwan and Asia. For more information, get Portfolio Grader’s complete analysis of CHT 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.