The overall ratings of four energy services stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Tenaris S.A. Sponsored ADR’s (TS) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Tenaris manufactures and supplies steel pipe products and related services for the world’s energy industry. TS also rates an F in Portfolio Grader’s specific subcategory of Sales Growth. To get an in-depth look at TS, get Portfolio Grader’s complete analysis of TS stock.

Slipping from a C to a D rating, Dril-Quip, Inc. (DRQ) takes a hit this week. Dril-Quip designs, manufactures, sells, and services offshore drilling and production equipment to be used in deepwater, harsh environment, and severe service applications. For more information, get Portfolio Grader’s complete analysis of DRQ stock.

Hornbeck Offshore Services, Inc. (HOS) ratings are on the decline this week as the company earns an F (“strong sell”). Last week, it received a D (“sell”). Hornbeck Offshore Services provides marine transportation services to the offshore oil and gas industry. The stock gets F’s in Earnings Revisions and Cash Flow. As of Oct. 16, 2014, 12.7% of outstanding Hornbeck Offshore Services, Inc. shares were held short. To get an in-depth look at HOS, get Portfolio Grader’s complete analysis of HOS stock.

Helix Energy Solutions Group, Inc. (HLX) is having a tough week. The company’s rating falls from a D to an F. Helix Energy Solutions is a marine contractor and operator of offshore oil and gas properties and production facilities. The stock gets F’s in Cash Flow and Margin Growth. For more information, get Portfolio Grader’s complete analysis of HLX 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.