This week, 3 Semiconductors & Semiconductor Equipment stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This is a rough week for SunPower Corporation (SPWR). The company’s rating falls to D from the previous week’s C. SunPower Corporation is a vertically integrated solar products and services company that designs, manufactures, and delivers solar electric systems worldwide for residential, commercial, and utility-scale power plant customers. The company also gets F’s in sales growth, earnings growth, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of SPWR stock.

Kopin Corporation (KOPN) slips from a C to a D this week. Kopin Corporation develops and manufactures semiconductor materials and small form factor displays. The company also gets F’s in sales growth, earnings surprise, and return on equity. For more information, get Portfolio Grader’s complete analysis of KOPN stock.

AXT, Inc.’s (AXTI) rating weakens this week, dropping to a D versus last week’s C. AXT, Inc. designs, develops, manufactures, and distributes compound and single element semiconductor substrates for use in wireless communications, lighting display applications, and fiber optic communications. The company also gets F’s in earnings growth. For more information, get Portfolio Grader’s complete analysis of AXTI 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.