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

Turquoise Hill Resources Ltd. (TRQ) is bettering its rating of C (“hold”) from last week to a B (“buy”) this week. Turquoise Hill Resources explores for and develops mineral and metal properties in Asia and Australia. In Portfolio Grader’s specific subcategory of Earnings Surprise, TRQ also gets an A. For more information, get Portfolio Grader’s complete analysis of TRQ stock.

This week, Agnico-Eagle Mines Limited’s (AEM) ratings are up from a C last week to a B. Agnico-Eagle Mines produces, explores for, and develops gold. For more information, get Portfolio Grader’s complete analysis of AEM stock.

Hudbay Minerals Inc.’s (HBM) ratings are looking better this week, moving up to a B from last week’s C. HudBay Minerals is a mining company that mines and produces zinc, copper, gold, and silver. For more information, get Portfolio Grader’s complete analysis of HBM stock.

Materion Corporation (MTRN) is seeing ratings go up from a C last week to a B this week. Materion produces and supplies high-performance engineered materials. For more information, get Portfolio Grader’s complete analysis of MTRN 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.