This week, 4 Aerospace & Defense stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This is a rough week for American Science and Engineering, Inc. (ASEI). The company’s rating falls to F from the previous week’s C. American Science and Engineering, Inc. is engaged in the development, manufacturing, marketing, and sale of X-ray inspection and similar detection solutions for homeland security and other targeted markets. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings revisions, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of ASEI stock.

Triumph Group, Inc. (TGI) declines this week from a D to a F. Triumph Group, Inc. designs, manufactures, and sells aviation products. For more information, get Portfolio Grader’s complete analysis of TGI stock.

Vectrus Inc (VEC) experiences a ratings drop this week, going from last week’s C to a D. For more information, get Portfolio Grader’s complete analysis of VEC stock.

Innovative Solutions and Support, Inc. (ISSC) earns a F this week, moving down from last week’s grade of D. Innovative Solutions and Support, Inc. designs, manufactures, and sells flight information computers, electronic displays, and advanced monitoring systems to the military and government, commercial air transport, and corporate aviation markets. The company also gets F’s in sales growth, operating margin growth, earnings surprise, and return on equity. For more information, get Portfolio Grader’s complete analysis of ISSC 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.