While it is true that owners of energy stock are in store for massive returns in the coming years due to the sector’s sustainability and growth opportunities, there are still some energy companies that are not as reliable as had once hoped. I watch more than 5,000 publicly traded companies with my Portfolio Grader tool, ranking companies by a number of fundamental and quantitative measures. And this week, I’ve got four energy stocks to put on your sell list.

Here they are, in alphabetical order. Each one of these stocks gets a “D” or “F” according to my research.

Exelon (NYSE:EXC) is a utility services holding company and one of the most recognizable energy companies in the world. In the last year, EXC stock has declined 6%. EXC stock gets a “D” for sales growth, a “D” for operating margin growth, a “D” for earnings growth, a “D” for its ability to exceed the consensus earnings estimates on Wall Street and a “D” for cash flow in my Portfolio Grader tool. For more information, view my complete analysis of EXC stock.

NRG Energy (NYSE:NRG) owns, develops, constructs and operates power generation facilities. NRG stock has dipped 17% in the last year, compared to a gain of 5% for the Dow Jones. NRG stock gets a “D” for sales growth, a “D” for operating margin growth, an “F” for earnings growth, a “D” for the magnitude in which earnings projections have increased over the past month, an “F” for cash flow and a “D” for return on equity in my Portfolio Grader tool. For more information, view my complete analysis of NRG stock.

PG&E (NYSE:PCG) is known best for owning Pacific Gas and Electric Company. In the last 12 months, PCG stock is down 10%. PCG stock gets a “D” for operating margin growth, a “D” for earnings growth and an “F” for cash flow in my Portfolio Grader tool. For more information, view my complete analysis of PCG stock.

Public Service Enterprise Group (NYSE:PEG) is another power and electric holding company on the list. A 5% drop in the past year has shareholders questioning their purchase. PEG stock gets an “F” for sales growth, a “D” for operating margin growth, a “D” for earnings growth and a “D” for cash flow in my Portfolio Grader tool. For more information, view my complete analysis of PEG stock.

Get more analysis of these picks and other publicly traded stocks with Louis Navellier’s Portfolio Grader tool, a 100% free stock rating tool that measures both quantitative buying pressure and eight fundamental factors.