Six Oil and Gas stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

SandRidge Permian Trust (NYSE:PER) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. The stock’s dividend yield is 2.5%. For more information, get Portfolio Grader’s complete analysis of PER stock.

Miller Energy Resources (NYSE:MILL) is seeing ratings go up from a C last week to a B this week. Miller Petroleum is an oil and gas exploration, production, and drilling firm. The stock price has risen 3.7% over the past month, better than the 4.4% decrease the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of MILL stock.

This week, StealthGas (NASDAQ:GASS) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). StealthGas offers marine transport services for liquefied petroleum gas producers and users. Shares of the company are up 6.1% from a month ago. The stock’s trailing PE Ratio is 5.79. For more information, get Portfolio Grader’s complete analysis of GASS stock.

Teekay LNG Partners (NYSE:TGP) improves from a C to a B rating this week. Teekay LNG Partners provides marine transportation services for liquefied natural gas, liquefied petroleum gas and crude oil. At present, the stock has a dividend yield of 2.7%. For more information, get Portfolio Grader’s complete analysis of TGP stock.

This week, Transmontaigne Partners (NYSE:TLP) pushes up from a C to a B rating. TransMontaigne Partners is a refined petroleum products terminaling and pipeline company with operations currently in Florida, Southwest Missouri and Northwest Arkansas. The stock has a dividend yield of 2.6%. For more information, get Portfolio Grader’s complete analysis of TLP stock.

Niska Gas Storage Partners (NYSE:NKA) shows solid improvement this week. The company’s rating rises from a C to a B. Niska Gas Storage is an independent owner and operator of natural gas storage assets in North America. For more information, get Portfolio Grader’s complete analysis of NKA 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.