For the current week, the overall ratings of four service stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, Coinstar (CSTR) falls to a D (“sell”), worse than last week’s grade of C (“hold”). 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 is a rough week for American Public Education, Inc. (APEI). The company’s rating falls to D from the previous week’s C. American Public Education provides online postsecondary education focusing on the needs of the military and public service communities. Shares of the stock have been changing hands at an unusually rapid pace, up 1318.4% from the week prior. To get an in-depth look at APEI, get Portfolio Grader’s complete analysis of APEI stock.

Career Education Corporation (CECO) earns a D this week, falling from last week’s grade of C. 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.

DeVry Education Group Inc. (DV) is having a tough week. The company’s rating falls from a C to a D. DeVry provides educational services worldwide and operates various institutions of higher education. As of Aug. 12, 2015, 15.8% of outstanding DeVry Education Group Inc. shares were held short. 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.