This week, five energy services stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Exterran Partners, L.P. (EXLP) is making progress this week as its rating of C (“hold”) from last week increases to a B (“buy”) rating this week. Exterran Partners offers natural gas compression services. In Portfolio Grader’s specific subcategory of Margin Growth, EXLP also gets an A. The stock has a dividend yield of 2.1%. For more information, get Portfolio Grader’s complete analysis of EXLP stock.

Synthesis Energy Systems, Inc. (SYMX) shows solid improvement this week. The company’s rating rises from a C to a B. Synthesis Energy Systems designs, invests in, builds, owns, and operates utility plants for industrial customers. Shares of the stock have been changing hands at an unusually rapid pace, up 955.6% from the week prior. For more information, get Portfolio Grader’s complete analysis of SYMX stock.

This week, Parker Drilling Company (PKD) pushes up from a C to a B rating. Parker Drilling provides contract drilling and related services. For more information, get Portfolio Grader’s complete analysis of PKD stock.

CARBO Ceramics (CRR) earns a B this week, jumping up from last week’s grade of C. CARBO Ceramics manufactures and supplies resin-coated ceramic and resin-coated sand proppants primarily used in the hydraulic fracturing of natural gas and oil wells in the United States and internationally. The stock price has been on the rise for the past five days, reaching $138.97. For more information, get Portfolio Grader’s complete analysis of CRR stock.

This is a strong week for Helmerich & Payne, Inc. (HP). The company’s rating climbs to B from the previous week’s C. Helmerich & Payne provides contract drilling of oil and gas wells in the Gulf of Mexico and South America. After five consecutive days of gains, the stock price has reached $109.68. At present, the stock has a dividend yield of 2.5%. For more information, get Portfolio Grader’s complete analysis of HP 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.