This week, the overall grades of three service stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

ATA, Inc. Sponsored ADR’s (ATAI) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. ATA offers services for the creation and delivery of computer-based tests based on its proprietary testing technologies and test delivery platform. In Portfolio Grader’s specific subcategories of Earnings Momentum and Sales Growth, ATAI also gets F’s. The stock’s trailing PE Ratio is 28.80. To get an in-depth look at ATAI, get Portfolio Grader’s complete analysis of ATAI stock.

The rating of Coinstar (CSTR) slips from a C to a D. Coinstar is a multi-national company that offers solutions for storefronts, including self-service coin counting, entertainment services, and self-service DVD kiosks. The stock also gets an F in Earnings Momentum. 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.

Matthews International Corporation Class A (MATW) earns a D this week, moving down from last week’s grade of C. Matthews International is a designer, manufacturer and marketer principally of memorialization products and brand solutions. To get an in-depth look at MATW, get Portfolio Grader’s complete analysis of MATW 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.