Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk (volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model Two out of the three major indices are trading lower today with the Dow Jones Industrial Average ( ^DJI) trading down 10 points (-0.1%) at 13,082 as of Monday, Nov. 5, 2012, 1:34 PM ET. The NYSE advances/declines ratio sits at 1,351 issues advancing vs. 1,574 declining with 129 unchanged. The Basic Materials sector currently sits up 0.4% versus the S&P 500, which is down 0.1%. On the negative front, top decliners within the sector include Chesapeake Energy ( CHK), down 2.1%, Total ( TOT), down 1.4%, Suncor Energy ( SU), down 1.3%, BP ( BP), down 0.9% and Occidental Petroleum Corporation ( OXY), down 0.5%. Top gainers within the sector include Turquoise Hill Resources ( TRQ), up 10.3%, Transocean ( RIG), up 4.6%, Agnico-Eagle Mines ( AEM), up 1.5%, Continental Resources ( CLR), up 1.2% and Gerdau ( GGB), up 1.6%. TheStreet Ratings group would like to highlight 4 stocks pushing the sector lower today: 4. Penn West Petroleum ( PWE) is one of the companies pushing the Basic Materials sector lower today. As of noon trading, Penn West Petroleum is down $0.52 (-4.2%) to $11.64 on heavy volume Thus far, 3.0 million shares of Penn West Petroleum exchanged hands as compared to its average daily volume of 1.6 million shares. The stock has ranged in price between $11.52-$12.10 after having opened the day at $12.10 as compared to the previous trading day's close of $12.15. Penn West Petroleum Ltd., an exploration and production company, engages in acquiring, exploring, developing, exploiting, and holding interests in petroleum and natural gas properties and related assets in Western Canada. Penn West Petroleum has a market cap of $6.2 billion and is part of the energy industry. The company has a P/E ratio of 4.9, below the S&P 500 P/E ratio of 17.7. Shares are down 34.0% year to date as of the close of trading on Friday. Currently there are 2 analysts that rate Penn West Petroleum a buy, no analysts rate it a sell, and 3 rate it a hold. TheStreet Ratings rates Penn West Petroleum as a hold. The company's strengths can be seen in multiple areas, such as its revenue growth, expanding profit margins and good cash flow from operations. However, as a counter to these strengths, we also find weaknesses including a generally disappointing performance in the stock itself, deteriorating net income and disappointing return on equity. Get the full Penn West Petroleum Ratings Report now.