3 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”).

CenturyLink, Inc. (CTL) earns a B this week, jumping up from last week’s grade of C. CenturyLink, Inc. is an integrated communications company engaged mainly in providing communications services, Internet and broadband services. The company also gets A’s in operating margin growth and free cash flow. For more information, get Portfolio Grader’s complete analysis of CTL stock.

Windstream Holdings, Inc. (WIN) shows solid improvement this week. The company’s rating rises from a C to a B. Windstream Holdings, Inc. is a company that provides communications and technology solutions, including high-speed Internet access, digital television services, and voice services. The company also gets A’s in earnings revisions. For more information, get Portfolio Grader’s complete analysis of WIN stock.

This is a strong week for Vonage Holdings Corp. (VG). The company’s rating climbs to B from the previous week’s C. Vonage Holdings Corp. is a provider of broadband Voice over Internet Protocol telephone services to residential and small office customers. The company also gets A’s in earnings surprise. For more information, get Portfolio Grader’s complete analysis of VG 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.