The overall ratings of 3 Energy Equipment & Services stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Exterran Corp. (EXTN) slips from a C to a D this week. The company also gets F’s in sales growth, operating margin growth, earnings growth, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of EXTN stock.

This week, PHI, Inc. Non-Voting’s (PHIIK) rating worsens to a F from the company’s D rating a week ago. PHI, Inc. Non-Voting provides helicopter transportation and related services. The company also gets F’s in sales growth, operating margin growth, and earnings growth. For more information, get Portfolio Grader’s complete analysis of PHIIK stock.

Seadrill Ltd. (SDRL) gets weaker ratings this week as last week’s C drops to a D. Seadrill Ltd. is an offshore drilling contractor that provides drilling and well services to the offshore industry. The company also gets F’s in sales growth, operating margin growth, and free cash flow. For more information, get Portfolio Grader’s complete analysis of SDRL 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.