The grades of three Tech Services stocks are on the rise this week on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

ExlService Holdings (NASDAQ:EXLS) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. ExlService Holdings provides offshore business process outsourcing solutions, primarily serving the needs of Global 1000 companies in the banking, financial services and insurance area. In Portfolio Grader’s specific subcategory of Sales Growth, EXLS also gets an A. The stock price has risen 8% over the past month, better than the 4% increase the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of EXLS stock.

The rating of Cardtronics (NASDAQ:CATM) moves up this week, rising from a C to a B. Cardtronics provides ATM management and equipment-related services to large and small retail merchants operators of facilities such as shopping malls and airports. For more information, get Portfolio Grader’s complete analysis of CATM stock.

This week, PRGX Global (NASDAQ:PRGX) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). PRGX Global provides recovery audit services to clients by auditing data for errors and overpayments, analyzing data for trends, and client advisory on improving financial performance. Investors seem to agree with the upgraded status of the stock, and have pushed the stock up 8.4% over the past month. For more information, get Portfolio Grader’s complete analysis of PRGX 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.