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

Coinstar (CSTR) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. Coinstar is a multi-national company that offers solutions for storefronts, including self-service coin counting, entertainment services, and self-service DVD kiosks. For Portfolio Grader’s specific subcategory of Earnings Momentum, CSTR also gets an F. As of Oct. 17, 2013, 34.2% of outstanding Coinstar shares were held short. For more information, get Portfolio Grader’s complete analysis of CSTR stock.

This week, American Public Education, Inc.’s (APEI) rating worsens to a D from the company’s C rating a week ago. American Public Education provides online postsecondary education focusing on the needs of the military and public service communities. To get an in-depth look at APEI, get Portfolio Grader’s complete analysis of APEI stock.

This week, Career Education Corporation (CECO) drops from a C to a D rating. Career Education provides on-ground private, for-profit, postsecondary education in the United States, in addition to having a presence in online education. The stock gets F’s in Equity, Cash Flow and Sales Growth. For more information, get Portfolio Grader’s complete analysis of CECO stock.

This is a rough week for DeVry Education Group Inc. (DV). The company’s rating falls to D from the previous week’s C. DeVry provides educational services worldwide and operates various institutions of higher education. To get an in-depth look at DV, get Portfolio Grader’s complete analysis of DV 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.