The ratings of five communications equipment stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

ARRIS Group, Inc. (ARRS) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. ARRIS is a global communications technology company specializing in the design and engineering of broadband network solutions. As of June 18, 2015, 10.6% of outstanding ARRIS Group, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ARRS stock.

Applied Optoelectronics, Inc.’s (AAOI) rating falls this week to an F (“strong sell”), down from last week’s C (“sell”). The stock gets F’s in Earnings Surprise and Cash Flow. As of June 18, 2015, 13% of outstanding Applied Optoelectronics, Inc. shares were held short. The stock’s trailing PE Ratio is 79.70. To get an in-depth look at AAOI, get Portfolio Grader’s complete analysis of AAOI stock.

Dragonwave Inc. (DRWI) earns a D this week, moving down from last week’s grade of C. DragonWave is a producer of high-capacity packet microwave solutions which support networking and other data transmission needs. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of DRWI stock.

This is a rough week for Clearfield, Inc. (CLFD). The company’s rating falls to F from the previous week’s D. Clearfield offers telecommunications equipment and products in the United States. The stock gets F’s in Earnings Growth, Earnings Momentum and Sales Growth. As of June 18, 2015, 11.7% of outstanding Clearfield, Inc. shares were held short. The trailing PE Ratio for the stock is 60.20. To get an in-depth look at CLFD, get Portfolio Grader’s complete analysis of CLFD stock.

Slipping from a C to a D rating, Sonus Networks, Inc. (SONS) takes a hit this week. Sonus Networks provides voice infrastructure solutions for wireline and wireless service providers. Shares of the stock have been trading at an exceptionally rapid pace, up twofold from the week prior. For more information, get Portfolio Grader’s complete analysis of SONS 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.